diff --git a/lumi2/__init__.py b/lumi2/__init__.py
index 630809b..c2508a6 100644
--- a/lumi2/__init__.py
+++ b/lumi2/__init__.py
@@ -54,6 +54,4 @@ def create_app(test_config=None):
     api.add_resource(webapi.GroupMemberResource, '/api/group/<string:groupname>/member/<string:username>')
     api.init_app(app)
 
-    # TODO create OUs
-
     return app
diff --git a/lumi2/usermanager.py b/lumi2/usermanager.py
index 4a314e3..f9c7523 100644
--- a/lumi2/usermanager.py
+++ b/lumi2/usermanager.py
@@ -33,6 +33,18 @@ def _init_static_images():
     
 
 
+@bp.before_app_first_request
+def _initialize_ldap_dit():
+    """Creates the OUs for users and groups if they do not exist yet."""
+
+    conn = ldap.get_connection()
+    if not ldap.ou_exists(conn, current_app.config['LDAP_USERS_OU']):
+        ldap.create_ou(conn, current_app.config['LDAP_USERS_OU'])
+    if not ldap.ou_exists(conn, current_app.config['LDAP_GROUPS_OU']):
+        ldap.create_ou(conn, current_app.config['LDAP_GROUPS_OU'])
+    conn.unbind()
+
+
 @bp.route('/')
 def index():
     """Home page view."""