diff --git a/Backend/MotoresArgentinosV2.Infrastructure/Services/SitemapGeneratorService.cs b/Backend/MotoresArgentinosV2.Infrastructure/Services/SitemapGeneratorService.cs
index 65dfef4..713f373 100644
--- a/Backend/MotoresArgentinosV2.Infrastructure/Services/SitemapGeneratorService.cs
+++ b/Backend/MotoresArgentinosV2.Infrastructure/Services/SitemapGeneratorService.cs
@@ -22,14 +22,19 @@ public class SitemapGeneratorService : BackgroundService
 
     private const string BaseUrl = "https://motoresargentinos.com";
 
-    // Rutas estáticas públicas del frontend con sus prioridades
-    private static readonly (string Path, string Priority, string ChangeFreq)[] StaticRoutes =
+    // Rutas estáticas cuyo contenido cambia con cada aviso nuevo (usan lastmod dinámico)
+    private static readonly (string Path, string Priority, string ChangeFreq)[] DynamicDateRoutes =
     [
-        ("/",           "1.0", "daily"),
-        ("/explorar",   "0.8", "daily"),
-        ("/publicar",   "0.6", "monthly"),
-        ("/vender",     "0.6", "monthly"),
-        ("/condiciones","0.3", "yearly"),
+        ("/",         "1.0", "daily"),
+        ("/explorar", "0.8", "daily"),
+    ];
+
+    // Rutas estáticas cuyo contenido rara vez cambia (sin lastmod para no mentirle a Google)
+    private static readonly (string Path, string Priority, string ChangeFreq)[] FixedRoutes =
+    [
+        ("/publicar",    "0.6", "monthly"),
+        ("/vender",      "0.6", "monthly"),
+        ("/condiciones", "0.3", "yearly"),
     ];
 
     public SitemapGeneratorService(IServiceProvider serviceProvider, ILogger<SitemapGeneratorService> logger)
@@ -77,27 +82,42 @@ public class SitemapGeneratorService : BackgroundService
             .Select(a => new { a.AdID, a.PublishedAt })
             .ToListAsync();
 
-        var now = DateTime.UtcNow.ToString("yyyy-MM-dd");
+        // Fecha del aviso más reciente (para rutas cuyo contenido cambia con nuevos avisos)
+        var latestPublished = activeAds
+            .Where(a => a.PublishedAt.HasValue)
+            .Max(a => a.PublishedAt)
+            ?.ToString("yyyy-MM-dd") ?? DateTime.UtcNow.ToString("yyyy-MM-dd");
+
         var sb = new StringBuilder();
 
         sb.AppendLine("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
         sb.AppendLine("<urlset xmlns=\"http://www.sitemaps.org/schemas/sitemap/0.9\">");
 
-        // 1. Rutas estáticas
-        foreach (var (path, priority, changeFreq) in StaticRoutes)
+        // 1. Rutas cuyo contenido cambia con cada aviso nuevo (/, /explorar)
+        foreach (var (path, priority, changeFreq) in DynamicDateRoutes)
         {
             sb.AppendLine("  <url>");
             sb.AppendLine($"    <loc>{BaseUrl}{path}</loc>");
-            sb.AppendLine($"    <lastmod>{now}</lastmod>");
+            sb.AppendLine($"    <lastmod>{latestPublished}</lastmod>");
             sb.AppendLine($"    <changefreq>{changeFreq}</changefreq>");
             sb.AppendLine($"    <priority>{priority}</priority>");
             sb.AppendLine("  </url>");
         }
 
-        // 2. Rutas dinámicas (vehículos activos)
+        // 2. Rutas fijas (sin lastmod — no mentirle a Google)
+        foreach (var (path, priority, changeFreq) in FixedRoutes)
+        {
+            sb.AppendLine("  <url>");
+            sb.AppendLine($"    <loc>{BaseUrl}{path}</loc>");
+            sb.AppendLine($"    <changefreq>{changeFreq}</changefreq>");
+            sb.AppendLine($"    <priority>{priority}</priority>");
+            sb.AppendLine("  </url>");
+        }
+
+        // 3. Rutas dinámicas (vehículos activos — lastmod = fecha de publicación real)
         foreach (var ad in activeAds)
         {
-            var lastmod = ad.PublishedAt?.ToString("yyyy-MM-dd") ?? now;
+            var lastmod = ad.PublishedAt?.ToString("yyyy-MM-dd") ?? latestPublished;
 
             sb.AppendLine("  <url>");
             sb.AppendLine($"    <loc>{BaseUrl}/vehiculo/{ad.AdID}</loc>");
@@ -120,8 +140,8 @@ public class SitemapGeneratorService : BackgroundService
         await File.WriteAllTextAsync(tempPath, sb.ToString(), Encoding.UTF8);
         File.Move(tempPath, outputPath, overwrite: true);
 
-        var totalUrls = StaticRoutes.Length + activeAds.Count;
+        var totalUrls = DynamicDateRoutes.Length + FixedRoutes.Length + activeAds.Count;
         _logger.LogInformation("Sitemap generado con {TotalUrls} URLs ({StaticCount} estáticas + {DynamicCount} vehículos). Archivo: {Path}",
-            totalUrls, StaticRoutes.Length, activeAds.Count, outputPath);
+            totalUrls, DynamicDateRoutes.Length + FixedRoutes.Length, activeAds.Count, outputPath);
     }
 }