diff --git a/src/api/SIGCM2.Domain/Entities/Product.cs b/src/api/SIGCM2.Domain/Entities/Product.cs
new file mode 100644
index 0000000..1962efb
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Entities/Product.cs
@@ -0,0 +1,172 @@
+namespace SIGCM2.Domain.Entities;
+
+/// <summary>
+/// Immutable product entity for the commercial catalog.
+/// Factory method ForCreation creates new products (Id=0).
+/// Mutation methods (With*) return new instances — original is never modified.
+/// Flag coherence (RequiresCategory/HasDuration) is enforced by Application handlers
+/// at creation/update time against the ProductType, NOT here in the entity.
+/// MedioId and ProductTypeId are immutable post-creation by design.
+/// </summary>
+public sealed class Product
+{
+    private const int NombreMaxLength = 300;
+
+    public int Id { get; }
+    public string Nombre { get; }
+    public int MedioId { get; }
+    public int ProductTypeId { get; }
+    public int? RubroId { get; }
+    public decimal BasePrice { get; }
+    public int? PriceDurationDays { get; }
+    public bool IsActive { get; }
+    public DateTime FechaCreacion { get; }
+    public DateTime? FechaModificacion { get; }
+
+    /// <summary>Full hydration constructor — used by the repository to reconstruct from DB rows.</summary>
+    public Product(
+        int id,
+        string nombre,
+        int medioId,
+        int productTypeId,
+        int? rubroId,
+        decimal basePrice,
+        int? priceDurationDays,
+        bool isActive,
+        DateTime fechaCreacion,
+        DateTime? fechaModificacion)
+    {
+        Id = id;
+        Nombre = nombre;
+        MedioId = medioId;
+        ProductTypeId = productTypeId;
+        RubroId = rubroId;
+        BasePrice = basePrice;
+        PriceDurationDays = priceDurationDays;
+        IsActive = isActive;
+        FechaCreacion = fechaCreacion;
+        FechaModificacion = fechaModificacion;
+    }
+
+    /// <summary>
+    /// Factory for a new Product. Id=0 — DB assigns via IDENTITY.
+    /// IsActive=true, FechaModificacion=null.
+    /// </summary>
+    public static Product ForCreation(
+        string nombre,
+        int medioId,
+        int productTypeId,
+        int? rubroId,
+        decimal basePrice,
+        int? priceDurationDays,
+        TimeProvider timeProvider)
+    {
+        ValidateNombre(nombre);
+        ValidateMedioId(medioId);
+        ValidateProductTypeId(productTypeId);
+        ValidateRubroId(rubroId);
+        ValidateBasePrice(basePrice);
+        ValidatePriceDurationDays(priceDurationDays);
+
+        return new Product(
+            id: 0,
+            nombre: nombre.Trim(),
+            medioId: medioId,
+            productTypeId: productTypeId,
+            rubroId: rubroId,
+            basePrice: basePrice,
+            priceDurationDays: priceDurationDays,
+            isActive: true,
+            fechaCreacion: timeProvider.GetUtcNow().UtcDateTime,
+            fechaModificacion: null);
+    }
+
+    public Product WithRenamed(string nuevoNombre, TimeProvider timeProvider)
+    {
+        ValidateNombre(nuevoNombre);
+        return new Product(Id, nuevoNombre.Trim(), MedioId, ProductTypeId, RubroId,
+            BasePrice, PriceDurationDays, IsActive, FechaCreacion,
+            timeProvider.GetUtcNow().UtcDateTime);
+    }
+
+    public Product WithUpdatedPrice(decimal basePrice, int? priceDurationDays, TimeProvider timeProvider)
+    {
+        ValidateBasePrice(basePrice);
+        ValidatePriceDurationDays(priceDurationDays);
+        return new Product(Id, Nombre, MedioId, ProductTypeId, RubroId,
+            basePrice, priceDurationDays, IsActive, FechaCreacion,
+            timeProvider.GetUtcNow().UtcDateTime);
+    }
+
+    public Product WithUpdatedCategory(int? rubroId, TimeProvider timeProvider)
+    {
+        ValidateRubroId(rubroId);
+        return new Product(Id, Nombre, MedioId, ProductTypeId, rubroId,
+            BasePrice, PriceDurationDays, IsActive, FechaCreacion,
+            timeProvider.GetUtcNow().UtcDateTime);
+    }
+
+    /// <summary>
+    /// Combo mutator: renames, updates price and category in one call.
+    /// Used by UpdateProductCommandHandler.
+    /// </summary>
+    public Product WithUpdated(string nombre, int? rubroId, decimal basePrice, int? priceDurationDays, TimeProvider timeProvider)
+    {
+        ValidateNombre(nombre);
+        ValidateRubroId(rubroId);
+        ValidateBasePrice(basePrice);
+        ValidatePriceDurationDays(priceDurationDays);
+        return new Product(Id, nombre.Trim(), MedioId, ProductTypeId, rubroId,
+            basePrice, priceDurationDays, IsActive, FechaCreacion,
+            timeProvider.GetUtcNow().UtcDateTime);
+    }
+
+    public Product WithDeactivated(TimeProvider timeProvider)
+        => new(Id, Nombre, MedioId, ProductTypeId, RubroId,
+            BasePrice, PriceDurationDays, isActive: false, FechaCreacion,
+            timeProvider.GetUtcNow().UtcDateTime);
+
+    // ── Private validators ────────────────────────────────────────────────────
+
+    private static void ValidateNombre(string nombre)
+    {
+        if (string.IsNullOrWhiteSpace(nombre))
+            throw new ArgumentException(
+                "El Nombre del producto no puede estar vacío o ser solo espacios.", nameof(nombre));
+        if (nombre.Length > NombreMaxLength)
+            throw new ArgumentException(
+                $"El Nombre del producto no puede superar los {NombreMaxLength} caracteres.", nameof(nombre));
+    }
+
+    private static void ValidateMedioId(int medioId)
+    {
+        if (medioId <= 0)
+            throw new ArgumentException("medioId debe ser un entero positivo.", nameof(medioId));
+    }
+
+    private static void ValidateProductTypeId(int productTypeId)
+    {
+        if (productTypeId <= 0)
+            throw new ArgumentException("productTypeId debe ser un entero positivo.", nameof(productTypeId));
+    }
+
+    private static void ValidateRubroId(int? rubroId)
+    {
+        if (rubroId.HasValue && rubroId.Value <= 0)
+            throw new ArgumentException(
+                "rubroId debe ser un entero positivo cuando no es nulo.", nameof(rubroId));
+    }
+
+    private static void ValidateBasePrice(decimal basePrice)
+    {
+        if (basePrice < 0m)
+            throw new ArgumentException("basePrice no puede ser negativo.", nameof(basePrice));
+    }
+
+    private static void ValidatePriceDurationDays(int? priceDurationDays)
+    {
+        if (priceDurationDays.HasValue && priceDurationDays.Value <= 0)
+            throw new ArgumentException(
+                "priceDurationDays debe ser >= 1 cuando se provee.", nameof(priceDurationDays));
+    }
+}
diff --git a/src/api/SIGCM2.Domain/Exceptions/ProductNombreDuplicadoEnMedioTipoException.cs b/src/api/SIGCM2.Domain/Exceptions/ProductNombreDuplicadoEnMedioTipoException.cs
new file mode 100644
index 0000000..7eed7b7
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/ProductNombreDuplicadoEnMedioTipoException.cs
@@ -0,0 +1,19 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when a Product with the same Nombre already exists for a given MedioId+ProductTypeId. → HTTP 409
+/// </summary>
+public sealed class ProductNombreDuplicadoEnMedioTipoException : DomainException
+{
+    public int MedioId { get; }
+    public int ProductTypeId { get; }
+    public string Nombre { get; }
+
+    public ProductNombreDuplicadoEnMedioTipoException(int medioId, int productTypeId, string nombre)
+        : base($"Ya existe un producto activo con nombre '{nombre}' para medioId={medioId} y productTypeId={productTypeId}.")
+    {
+        MedioId = medioId;
+        ProductTypeId = productTypeId;
+        Nombre = nombre;
+    }
+}
diff --git a/src/api/SIGCM2.Domain/Exceptions/ProductNotFoundException.cs b/src/api/SIGCM2.Domain/Exceptions/ProductNotFoundException.cs
new file mode 100644
index 0000000..912b362
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/ProductNotFoundException.cs
@@ -0,0 +1,15 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when a requested Product does not exist. → HTTP 404
+/// </summary>
+public sealed class ProductNotFoundException : DomainException
+{
+    public int ProductId { get; }
+
+    public ProductNotFoundException(int id)
+        : base($"El producto con id={id} no existe.")
+    {
+        ProductId = id;
+    }
+}
diff --git a/src/api/SIGCM2.Domain/Exceptions/ProductTipoFlagsIncoherentesException.cs b/src/api/SIGCM2.Domain/Exceptions/ProductTipoFlagsIncoherentesException.cs
new file mode 100644
index 0000000..9cc9805
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/ProductTipoFlagsIncoherentesException.cs
@@ -0,0 +1,16 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when a Product's field violates the flags coherence rules of its ProductType
+/// (e.g. RequiresCategory=true but RubroId is null, or HasDuration=true but PriceDurationDays is null). → HTTP 422
+/// </summary>
+public sealed class ProductTipoFlagsIncoherentesException : DomainException
+{
+    public string Field { get; }
+
+    public ProductTipoFlagsIncoherentesException(string reason, string field)
+        : base($"Incoherencia de flags del tipo de producto: {reason}.")
+    {
+        Field = field;
+    }
+}
diff --git a/src/api/SIGCM2.Domain/Exceptions/ProductTypeInactivoException.cs b/src/api/SIGCM2.Domain/Exceptions/ProductTypeInactivoException.cs
new file mode 100644
index 0000000..f853221
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/ProductTypeInactivoException.cs
@@ -0,0 +1,15 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when attempting to create/update a Product referencing an inactive ProductType. → HTTP 422
+/// </summary>
+public sealed class ProductTypeInactivoException : DomainException
+{
+    public int ProductTypeId { get; }
+
+    public ProductTypeInactivoException(int productTypeId)
+        : base($"El tipo de producto con id={productTypeId} está inactivo y no puede asignarse a un producto.")
+    {
+        ProductTypeId = productTypeId;
+    }
+}
diff --git a/src/api/SIGCM2.Domain/Exceptions/RubroInactivoException.cs b/src/api/SIGCM2.Domain/Exceptions/RubroInactivoException.cs
new file mode 100644
index 0000000..7bbea89
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/RubroInactivoException.cs
@@ -0,0 +1,15 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when attempting to create/update a Product referencing an inactive Rubro. → HTTP 422
+/// </summary>
+public sealed class RubroInactivoException : DomainException
+{
+    public int RubroId { get; }
+
+    public RubroInactivoException(int rubroId)
+        : base($"El rubro con id={rubroId} está inactivo y no puede asignarse a un producto.")
+    {
+        RubroId = rubroId;
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Domain/ProductTests.cs b/tests/SIGCM2.Application.Tests/Domain/ProductTests.cs
new file mode 100644
index 0000000..d7e6e41
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Domain/ProductTests.cs
@@ -0,0 +1,218 @@
+using FluentAssertions;
+using Microsoft.Extensions.Time.Testing;
+using SIGCM2.Domain.Entities;
+
+namespace SIGCM2.Application.Tests.Domain;
+
+/// <summary>
+/// PRD-002 — Domain entity tests for Product.
+/// Validates factory method, mutation methods, and validation rules.
+/// </summary>
+public class ProductTests
+{
+    private static readonly FakeTimeProvider _time =
+        new(new DateTimeOffset(2026, 4, 19, 10, 0, 0, TimeSpan.Zero));
+
+    private static Product ValidProduct(int? rubroId = null, int? priceDurationDays = null)
+        => Product.ForCreation(
+            nombre: "Clasificado Estándar",
+            medioId: 1,
+            productTypeId: 2,
+            rubroId: rubroId,
+            basePrice: 100.50m,
+            priceDurationDays: priceDurationDays,
+            timeProvider: _time);
+
+    // ── R1-S1: ForCreation happy path ─────────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_ValidData_ReturnsEntityWithDefaults()
+    {
+        var p = ValidProduct();
+
+        p.IsActive.Should().BeTrue();
+        p.Id.Should().Be(0);
+        p.FechaCreacion.Should().Be(_time.GetUtcNow().UtcDateTime);
+        p.FechaModificacion.Should().BeNull();
+        p.Nombre.Should().Be("Clasificado Estándar");
+        p.MedioId.Should().Be(1);
+        p.ProductTypeId.Should().Be(2);
+        p.RubroId.Should().BeNull();
+        p.BasePrice.Should().Be(100.50m);
+        p.PriceDurationDays.Should().BeNull();
+    }
+
+    // ── R1-S2: Nombre vacío ────────────────────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_EmptyNombre_ThrowsArgumentException()
+    {
+        var act = () => Product.ForCreation("", 1, 2, null, 10m, null, _time);
+
+        act.Should().Throw<ArgumentException>()
+            .WithMessage("*Nombre*");
+    }
+
+    // ── R1-S3: Nombre solo espacios ────────────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_WhitespaceNombre_ThrowsArgumentException()
+    {
+        var act = () => Product.ForCreation("   ", 1, 2, null, 10m, null, _time);
+
+        act.Should().Throw<ArgumentException>();
+    }
+
+    // ── R1-S4: BasePrice negativo ──────────────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_NegativeBasePrice_ThrowsArgumentException()
+    {
+        var act = () => Product.ForCreation("Test", 1, 2, null, -1m, null, _time);
+
+        act.Should().Throw<ArgumentException>()
+            .WithMessage("*basePrice*");
+    }
+
+    // ── R1-S5: BasePrice = 0 es válido ─────────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_ZeroBasePrice_DoesNotThrow()
+    {
+        var act = () => Product.ForCreation("Test", 1, 2, null, 0m, null, _time);
+
+        act.Should().NotThrow();
+    }
+
+    // ── R1-S6: PriceDurationDays = 0 ──────────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_ZeroPriceDurationDays_ThrowsArgumentException()
+    {
+        var act = () => Product.ForCreation("Test", 1, 2, null, 10m, 0, _time);
+
+        act.Should().Throw<ArgumentException>()
+            .WithMessage("*priceDurationDays*");
+    }
+
+    // ── R1-S7: PriceDurationDays negativo ─────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_NegativePriceDurationDays_ThrowsArgumentException()
+    {
+        var act = () => Product.ForCreation("Test", 1, 2, null, 10m, -5, _time);
+
+        act.Should().Throw<ArgumentException>();
+    }
+
+    // ── R1-S8: PriceDurationDays válido ───────────────────────────────────────
+
+    [Fact]
+    public void ForCreation_ValidPriceDurationDays_SetsValue()
+    {
+        var p = Product.ForCreation("Test", 1, 2, null, 10m, 30, _time);
+
+        p.PriceDurationDays.Should().Be(30);
+    }
+
+    // ── R1-S9: WithDeactivated ─────────────────────────────────────────────────
+
+    [Fact]
+    public void WithDeactivated_ActiveProduct_ReturnsInactiveWithModDate()
+    {
+        var product = ValidProduct();
+        var tp2 = new FakeTimeProvider(new DateTimeOffset(2026, 4, 20, 12, 0, 0, TimeSpan.Zero));
+
+        var deactivated = product.WithDeactivated(tp2);
+
+        deactivated.IsActive.Should().BeFalse();
+        deactivated.FechaModificacion.Should().Be(tp2.GetUtcNow().UtcDateTime);
+        // Immutability: original unchanged
+        product.IsActive.Should().BeTrue();
+    }
+
+    // ── R1-S10: WithDeactivated idempotente ───────────────────────────────────
+
+    [Fact]
+    public void WithDeactivated_AlreadyInactive_ReturnsInactiveNoProblem()
+    {
+        var product = ValidProduct();
+        var deactivated = product.WithDeactivated(_time);
+
+        var act = () => deactivated.WithDeactivated(_time);
+
+        act.Should().NotThrow();
+        act().IsActive.Should().BeFalse();
+    }
+
+    // ── R1-S11: WithUpdated ───────────────────────────────────────────────────
+
+    [Fact]
+    public void WithUpdated_ValidFields_ReturnsNewInstanceWithUpdatedValues()
+    {
+        var product = ValidProduct();
+        var tp2 = new FakeTimeProvider(new DateTimeOffset(2026, 4, 20, 12, 0, 0, TimeSpan.Zero));
+
+        var updated = product.WithUpdated("Nuevo Nombre", rubroId: null, basePrice: 200m, priceDurationDays: 15, tp2);
+
+        updated.Nombre.Should().Be("Nuevo Nombre");
+        updated.BasePrice.Should().Be(200m);
+        updated.PriceDurationDays.Should().Be(15);
+        updated.FechaModificacion.Should().Be(tp2.GetUtcNow().UtcDateTime);
+        // Immutability: original unchanged
+        product.Nombre.Should().Be("Clasificado Estándar");
+        product.BasePrice.Should().Be(100.50m);
+    }
+
+    // ── Immutability: With* return new instances ──────────────────────────────
+
+    [Fact]
+    public void WithRenamed_ReturnsNewInstance()
+    {
+        var p = ValidProduct();
+        var renamed = p.WithRenamed("Nuevo", _time);
+
+        renamed.Should().NotBeSameAs(p);
+        renamed.Nombre.Should().Be("Nuevo");
+    }
+
+    [Fact]
+    public void WithUpdatedPrice_ReturnsNewInstance()
+    {
+        var p = ValidProduct();
+        var updated = p.WithUpdatedPrice(999m, null, _time);
+
+        updated.Should().NotBeSameAs(p);
+        updated.BasePrice.Should().Be(999m);
+    }
+
+    [Fact]
+    public void WithUpdatedCategory_ReturnsNewInstance()
+    {
+        var p = ValidProduct();
+        var updated = p.WithUpdatedCategory(5, _time);
+
+        updated.Should().NotBeSameAs(p);
+        updated.RubroId.Should().Be(5);
+    }
+
+    // ── MedioId and ProductTypeId are immutable ───────────────────────────────
+
+    [Fact]
+    public void Product_HasNoMethodToChangeMedioId()
+    {
+        var type = typeof(Product);
+        var methods = type.GetMethods(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance);
+
+        methods.Should().NotContain(m => m.Name.Contains("Medio") && m.Name.StartsWith("With"));
+    }
+
+    [Fact]
+    public void Product_HasNoMethodToChangeProductTypeId()
+    {
+        var type = typeof(Product);
+        var methods = type.GetMethods(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance);
+
+        methods.Should().NotContain(m => m.Name.Contains("ProductType") && m.Name.StartsWith("With"));
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Products/Exceptions/ProductExceptionsTests.cs b/tests/SIGCM2.Application.Tests/Products/Exceptions/ProductExceptionsTests.cs
new file mode 100644
index 0000000..43d3de4
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Products/Exceptions/ProductExceptionsTests.cs
@@ -0,0 +1,60 @@
+using FluentAssertions;
+using SIGCM2.Domain.Exceptions;
+
+namespace SIGCM2.Application.Tests.Products.Exceptions;
+
+/// <summary>
+/// PRD-002 — Tests for new Product domain exceptions.
+/// Verifies message content and property values.
+/// </summary>
+public class ProductExceptionsTests
+{
+    [Fact]
+    public void ProductNotFoundException_ContainsId_InMessage()
+    {
+        var ex = new ProductNotFoundException(5);
+
+        ex.Message.Should().Contain("5");
+        ex.ProductId.Should().Be(5);
+    }
+
+    [Fact]
+    public void ProductNombreDuplicadoEnMedioTipoException_ContainsDetails()
+    {
+        var ex = new ProductNombreDuplicadoEnMedioTipoException(2, 3, "Clasificado");
+
+        ex.Message.Should().Contain("Clasificado");
+        ex.Message.Should().Contain("2");
+        ex.Message.Should().Contain("3");
+        ex.MedioId.Should().Be(2);
+        ex.ProductTypeId.Should().Be(3);
+        ex.Nombre.Should().Be("Clasificado");
+    }
+
+    [Fact]
+    public void ProductTipoFlagsIncoherentesException_FieldAndMessage()
+    {
+        var ex = new ProductTipoFlagsIncoherentesException("requiere RubroId", "rubroId");
+
+        ex.Field.Should().Be("rubroId");
+        ex.Message.Should().Contain("requiere RubroId");
+    }
+
+    [Fact]
+    public void ProductTypeInactivoException_ContainsProductTypeId()
+    {
+        var ex = new ProductTypeInactivoException(7);
+
+        ex.Message.Should().Contain("7");
+        ex.ProductTypeId.Should().Be(7);
+    }
+
+    [Fact]
+    public void RubroInactivoException_ContainsRubroId()
+    {
+        var ex = new RubroInactivoException(12);
+
+        ex.Message.Should().Contain("12");
+        ex.RubroId.Should().Be(12);
+    }
+}