diff --git a/src/main/java/mops/gruppen2/controller/Gruppen2Controller.java b/src/main/java/mops/gruppen2/controller/Gruppen2Controller.java
index aa663c1..e2b7107 100644
--- a/src/main/java/mops/gruppen2/controller/Gruppen2Controller.java
+++ b/src/main/java/mops/gruppen2/controller/Gruppen2Controller.java
@@ -6,6 +6,7 @@ import mops.gruppen2.domain.Role;
 import mops.gruppen2.domain.User;
 import mops.gruppen2.domain.exception.EventException;
 import mops.gruppen2.domain.exception.GroupNotFoundException;
+import mops.gruppen2.domain.exception.NoAdminAfterActionException;
 import mops.gruppen2.security.Account;
 import mops.gruppen2.service.ControllerService;
 import mops.gruppen2.service.CsvService;
@@ -205,6 +206,7 @@ public class Gruppen2Controller {
     public String pLeaveGroup(KeycloakAuthenticationToken token, @RequestParam("group_id") Long groupId) throws EventException {
         Account account = keyCloakService.createAccountFromPrincipal(token);
         User user = new User(account.getName(), account.getGivenname(), account.getFamilyname(), account.getEmail());
+        controllerService.passIfLastAdmin(account, groupId);
         controllerService.deleteUser(user.getId(), groupId);
         return "redirect:/gruppen2/";
     }
@@ -229,15 +231,22 @@ public class Gruppen2Controller {
     @PostMapping("/details/members/changeRole")
     public String changeRole(KeycloakAuthenticationToken token, @RequestParam("group_id") Long groupId,
                              @RequestParam("user_id") String userId) throws EventException {
+
+
         Account account = keyCloakService.createAccountFromPrincipal(token);
+        if (userId.equals(account.getName())) {
+            if (controllerService.passIfLastAdmin(account, groupId)){
+                throw new NoAdminAfterActionException("Du otto bist letzter Admin");
+            }
+            controllerService.updateRole(userId, groupId);
+            return "redirect:/gruppen2/details/" + groupId;
+        }
         controllerService.updateRole(userId, groupId);
-        if(userId.equals(account.getName())) return "redirect:/gruppen2/details/" + groupId;
         return "redirect:/gruppen2/details/members/" + groupId;
     }
 
     @RolesAllowed({"ROLE_orga", "ROLE_studentin", "ROLE_actuator)"})
     @PostMapping("/details/members/deleteUser")
-
     public String deleteUser(KeycloakAuthenticationToken token, @RequestParam("group_id") Long groupId,
                              @RequestParam("user_id") String userId) throws EventException {
         controllerService.deleteUser(userId, groupId);
diff --git a/src/main/java/mops/gruppen2/domain/exception/NoAdminAfterActionException.java b/src/main/java/mops/gruppen2/domain/exception/NoAdminAfterActionException.java
new file mode 100644
index 0000000..f0b170b
--- /dev/null
+++ b/src/main/java/mops/gruppen2/domain/exception/NoAdminAfterActionException.java
@@ -0,0 +1,10 @@
+package mops.gruppen2.domain.exception;
+
+import org.springframework.http.HttpStatus;
+
+public class NoAdminAfterActionException extends EventException {
+
+    public NoAdminAfterActionException(String info) {
+        super(HttpStatus.INTERNAL_SERVER_ERROR, "Nach dieser Aktion hätte die Gruppe keinen Admin mehr", info);
+    }
+}
diff --git a/src/main/java/mops/gruppen2/service/ControllerService.java b/src/main/java/mops/gruppen2/service/ControllerService.java
index 81ce51a..9316fe9 100644
--- a/src/main/java/mops/gruppen2/service/ControllerService.java
+++ b/src/main/java/mops/gruppen2/service/ControllerService.java
@@ -18,8 +18,11 @@ import mops.gruppen2.security.Account;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 
+import static mops.gruppen2.domain.Role.ADMIN;
+
 
 @Service
 public class ControllerService {
@@ -104,10 +107,10 @@ public class ControllerService {
             throw new UserNotFoundException(this.getClass().toString());
         }
 
-        if (group.getRoles().get(user.getId()) == Role.ADMIN) {
+        if (group.getRoles().get(user.getId()) == ADMIN) {
             updateRoleEvent = new UpdateRoleEvent(groupId, user.getId(), Role.MEMBER);
         } else {
-            updateRoleEvent = new UpdateRoleEvent(groupId, user.getId(), Role.ADMIN);
+            updateRoleEvent = new UpdateRoleEvent(groupId, user.getId(), ADMIN);
         }
         eventService.saveEvent(updateRoleEvent);
     }
@@ -153,4 +156,37 @@ public class ControllerService {
         updateRole(account.getName(), groupId);
         addUserList(users, groupId);
     }
+
+    public boolean passIfLastAdmin(Account account, Long groupId){
+        Group group = userService.getGroupById(groupId);
+        if (group.getMembers().size() <= 1){
+            return true;
+        }
+
+        if (isLastAdmin(account, group)){
+            String newAdminId = getVeteranMember(account, group);
+            updateRole(newAdminId, groupId);
+        }
+        return false;
+    }
+
+    private boolean isLastAdmin(Account account, Group group){
+        for (Map.Entry<String, Role> entry : group.getRoles().entrySet()){
+            if (entry.getValue().equals(ADMIN)){
+                if (!(entry.getKey().equals(account.getName()))){
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private String getVeteranMember(Account account, Group group){
+        List<User> mitglieder = group.getMembers();
+        if (mitglieder.get(0).getId().equals(account.getName())){
+            return mitglieder.get(1).getId();
+        }
+        return mitglieder.get(0).getId();
+    }
+
 }