diff --git a/backend/src/main/java/core/repositories/timemanager/TaskgroupRepository.java b/backend/src/main/java/core/repositories/timemanager/TaskgroupRepository.java
index 6441145..4c17014 100644
--- a/backend/src/main/java/core/repositories/timemanager/TaskgroupRepository.java
+++ b/backend/src/main/java/core/repositories/timemanager/TaskgroupRepository.java
@@ -2,10 +2,12 @@ package core.repositories.timemanager;
 
 import core.entities.User;
 import core.entities.timemanager.Taskgroup;
+import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.stereotype.Repository;
 
+import javax.transaction.Transactional;
 import java.util.List;
 
 @Repository
@@ -15,4 +17,8 @@ public interface TaskgroupRepository extends CrudRepository<Taskgroup, Long> {
 
     @Query("SELECT tg FROM Taskgroup tg WHERE tg.user.username = ?1")
     List<Taskgroup> findAllByUser(String username);
+
+    @Modifying
+    @Transactional
+    void deleteAllByUser(User user);
 }
diff --git a/backend/src/main/java/core/services/TaskgroupService.java b/backend/src/main/java/core/services/TaskgroupService.java
index 07cd12e..d5031c8 100644
--- a/backend/src/main/java/core/services/TaskgroupService.java
+++ b/backend/src/main/java/core/services/TaskgroupService.java
@@ -71,4 +71,8 @@ public class TaskgroupService {
     public List<Taskgroup> getTaskgroupsByUser(String username) {
         return taskgroupRepository.findAllByUser(username);
     }
+
+    public void deleteTaskgroupByUser(User user) {
+        taskgroupRepository.deleteAllByUser(user);
+    }
 }
diff --git a/backend/src/main/java/core/services/UserService.java b/backend/src/main/java/core/services/UserService.java
index 2ed47f9..e149fbe 100644
--- a/backend/src/main/java/core/services/UserService.java
+++ b/backend/src/main/java/core/services/UserService.java
@@ -9,6 +9,7 @@ import core.api.models.users.UserUpdateInfo;
 import core.entities.RoleEntity;
 import core.entities.User;
 import core.entities.UserRole;
+import core.entities.timemanager.Taskgroup;
 import core.repositories.RoleRepository;
 import core.repositories.UserRepository;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -29,6 +30,7 @@ public class UserService {
 
     @Autowired
     private RoleRepository roleRepository;
+    @Autowired private TaskgroupService taskgroupService;
 
     public List<UserInfo> getAllUserInfos() {
         Iterable<User> users = userRepository.findAll();
@@ -146,6 +148,7 @@ public class UserService {
             return 2;
         }
 
+        taskgroupService.deleteTaskgroupByUser(requestedUser.get());
         userRepository.deleteByUsername(username);
         return 0;
     }