diff --git a/cms/server/contest/handlers/main.py b/cms/server/contest/handlers/main.py
index 2b3e60f160..012b835fc2 100644
--- a/cms/server/contest/handlers/main.py
+++ b/cms/server/contest/handlers/main.py
@@ -113,8 +113,9 @@ def post(self):
 
         # Create participation
         team = self._get_team()
-        participation = Participation(user=user, contest=self.contest,
-                                      team=team)
+        participation = Participation(
+            user=user, contest=self.contest, team=team, group=self.contest.main_group
+        )
         self.sql_session.add(participation)
 
         self.sql_session.commit()