diff --git a/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs b/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs
index 0060fa5..297b5ec 100644
--- a/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs
+++ b/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs
@@ -64,6 +64,9 @@ public static class DependencyInjection
 
         services.AddScoped(typeof(IRepository<>), typeof(Repository<>));
 
+        // AutoMapper - Register entity self-mappings (T -> T) for generic repository
+        services.AddAutoMapper(config => config.AddMaps(typeof(EntitySelfMappingProfile).Assembly));
+
         return services;
     }
 }
diff --git a/src/infrastructure/DigitalData.MessagingService.Infrastructure/Mappings/EntitySelfMappingProfile.cs b/src/infrastructure/DigitalData.MessagingService.Infrastructure/Mappings/EntitySelfMappingProfile.cs
new file mode 100644
index 0000000..05ff608
--- /dev/null
+++ b/src/infrastructure/DigitalData.MessagingService.Infrastructure/Mappings/EntitySelfMappingProfile.cs
@@ -0,0 +1,19 @@
+using AutoMapper;
+using DigitalData.MessagingService.Domain.Entities;
+
+namespace DigitalData.MessagingService.Infrastructure.Mappings;
+
+/// <summary>
+/// AutoMapper profile that registers self-mappings (T -> T) for all domain entities.
+/// This allows AutoMapper to be used uniformly in the generic repository
+/// regardless of whether TDto is a DTO or the entity type itself.
+/// </summary>
+public class EntitySelfMappingProfile : Profile
+{
+    public EntitySelfMappingProfile()
+    {
+        CreateMap<EmailAccount, EmailAccount>();
+        CreateMap<ReceivedEmail, ReceivedEmail>();
+        CreateMap<EmailAttachment, EmailAttachment>();
+    }
+}