diff --git a/colloscope/icalexport.py b/colloscope/icalexport.py
index bc7a8b0..2ca1f68 100644
--- a/colloscope/icalexport.py
+++ b/colloscope/icalexport.py
@@ -45,7 +45,7 @@ def to_calendar(etudiant, periode):
         event.add("dtstart", start, parameters={"tzid": LOCAL_TZ})
         event.add("dtend", fin, parameters={"tzid": LOCAL_TZ})
         event.add("dtstamp", datetime.now())
-        event.add("uid", str(uuid4()))
+        event.add("uid", str(rotation.id))
 
         event.add("location", f"{rotation.creneau.salle} ({rotation.creneau.periode.classe.lycee})")
         event.add("categories", "COLLE-" + str(rotation.creneau.matiere))