diff --git a/src/main/java/com/knecon/fforesight/tenantusermanagement/service/UserService.java b/src/main/java/com/knecon/fforesight/tenantusermanagement/service/UserService.java
index 1b0dc79..77b865e 100644
--- a/src/main/java/com/knecon/fforesight/tenantusermanagement/service/UserService.java
+++ b/src/main/java/com/knecon/fforesight/tenantusermanagement/service/UserService.java
@@ -73,6 +73,10 @@ public class UserService {
     @CacheEvict(value = "${commons.keycloak.userCache}", allEntries = true, beforeInvocation = true)
     public User createUser(CreateUserRequest user) {
 
+        if (StringUtils.isEmpty(user.getEmail())) {
+            throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "Email address must be set");
+        }
+
         String username = StringUtils.isEmpty(user.getUsername()) ? user.getEmail() : user.getUsername();
         if (!this.getTenantUsersResource().search(username).isEmpty()) {
             throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "User with this username already exists");
diff --git a/src/test/java/com/knecon/fforesight/tenantusermanagement/tests/UserTest.java b/src/test/java/com/knecon/fforesight/tenantusermanagement/tests/UserTest.java
index ffd2030..e79d4ba 100644
--- a/src/test/java/com/knecon/fforesight/tenantusermanagement/tests/UserTest.java
+++ b/src/test/java/com/knecon/fforesight/tenantusermanagement/tests/UserTest.java
@@ -2,6 +2,8 @@ package com.knecon.fforesight.tenantusermanagement.tests;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.HashSet;
 import java.util.List;
@@ -133,5 +135,21 @@ public class UserTest extends AbstractTenantUserManagementIntegrationTest {
         }
 
     }
+    
+    @Test
+    public void testCreateUserWithoutMail() {
+
+        TenantContext.setTenantId(AbstractTenantUserManagementIntegrationTest.TEST_TENANT_ID);
+
+        CreateUserRequest createUserRequest = new CreateUserRequest();
+        createUserRequest.setFirstName("Test");
+        createUserRequest.setLastName("New User");
+        createUserRequest.setUsername(createUserRequest.getEmail());
+        createUserRequest.setRoles(tenantUserManagementProperties.getKcRoleMapping().getAllRoles());
+        // Optionally, you can also check the status code of the exception
+        FeignException e = assertThrows(FeignException.class, () -> userClient.createUser(createUserRequest));
+        assertEquals(400, e.status());
+
+    }
 
 }