diff --git a/docs/changelog.rst b/docs/changelog.rst
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -24,7 +24,7 @@ fixes
 - fixes #366 When Setting Repository Group To Blank Repo Group Wont Be 
   Moved To Root
 - fixes #371 fixed issues with beaker/sqlalchemy and non-ascii cache keys 
-
+- fixed #373 missing cascade drop on user_group_to_perm table
 
 1.3.1 (**2012-02-27**)
 ----------------------
diff --git a/rhodecode/controllers/admin/users_groups.py b/rhodecode/controllers/admin/users_groups.py
--- a/rhodecode/controllers/admin/users_groups.py
+++ b/rhodecode/controllers/admin/users_groups.py
@@ -160,11 +160,12 @@ class UsersGroupsController(BaseControll
 
         try:
             UsersGroupModel().delete(id)
+            Session.commit()
             h.flash(_('successfully deleted users group'), category='success')
-            Session.commit()
         except UsersGroupsAssignedException, e:
             h.flash(e, category='error')
         except Exception:
+            log.error(traceback.format_exc())
             h.flash(_('An error occurred during deletion of users group'),
                     category='error')
         return redirect(url('users_groups'))
diff --git a/rhodecode/model/db.py b/rhodecode/model/db.py
--- a/rhodecode/model/db.py
+++ b/rhodecode/model/db.py
@@ -400,7 +400,7 @@ class UserLog(Base, BaseModel):
         return datetime.date(*self.action_date.timetuple()[:3])
 
     user = relationship('User')
-    repository = relationship('Repository',cascade='')
+    repository = relationship('Repository', cascade='')
 
 
 class UsersGroup(Base, BaseModel):
@@ -412,6 +412,7 @@ class UsersGroup(Base, BaseModel):
     users_group_active = Column("users_group_active", Boolean(), nullable=True, unique=None, default=None)
 
     members = relationship('UsersGroupMember', cascade="all, delete, delete-orphan", lazy="joined")
+    users_group_to_perm = relationship('UsersGroupToPerm', cascade='all')
 
     def __repr__(self):
         return '<userGroup(%s)>' % (self.users_group_name)