diff --git a/eeg_backend/src/test/java/at/mueller/eeg/backend/iam/service/AuthServiceTest.java b/eeg_backend/src/test/java/at/mueller/eeg/backend/iam/service/AuthServiceTest.java
index e3563f5..530f193 100644
--- a/eeg_backend/src/test/java/at/mueller/eeg/backend/iam/service/AuthServiceTest.java
+++ b/eeg_backend/src/test/java/at/mueller/eeg/backend/iam/service/AuthServiceTest.java
@@ -20,6 +20,7 @@ import org.springframework.security.core.authority.SimpleGrantedAuthority;
 import org.springframework.security.oauth2.jwt.JwtEncoder;
 import org.springframework.security.oauth2.jwt.JwtEncoderParameters;
 
+import java.time.LocalDateTime;
 import java.util.List;
 import java.util.Optional;
 import java.util.UUID;
@@ -80,6 +81,25 @@ class AuthServiceTest {
         verify(mailService).sendVerificationEmail(eq("test@example.com"), anyString());
     }
 
+    @Test
+    void register_setsCreatedAt() {
+        IamDtos.RegistrationRequest request = new IamDtos.RegistrationRequest(
+                ParticipantType.PRIVATE, "Test", "Benutzer", null, "test@example.com", "password123"
+        );
+
+        when(userRepository.findByEmail("test@example.com")).thenReturn(Optional.empty());
+        when(userMapper.mapToEntity(any(), any())).thenReturn(testUser);
+        when(userRepository.save(any())).thenReturn(testUser);
+
+        LocalDateTime before = LocalDateTime.now().minusSeconds(1);
+        authService.register(request);
+        LocalDateTime after = LocalDateTime.now().plusSeconds(1);
+
+        assertNotNull(testUser.getCreatedAt());
+        assertFalse(testUser.getCreatedAt().isBefore(before), "createdAt should not be before registration started");
+        assertFalse(testUser.getCreatedAt().isAfter(after), "createdAt should not be after registration ended");
+    }
+
     @Test
     void register_duplicateEmail_throws() {
         IamDtos.RegistrationRequest request = new IamDtos.RegistrationRequest(