diff --git a/contract.py b/contract.py
index 60b35b0..b2bca88 100644
--- a/contract.py
+++ b/contract.py
@@ -150,7 +150,10 @@ class Contract(Workflow, ModelSQL, ModelView):
     @ModelView.button
     @Workflow.transition('cancelled')
     def cancelled(cls, contracts):
-        pass
+        contract = contracts[0]
+        for equipment in contract.equipments:
+            equipment.state = "uncontrated"
+            equipment.save()
 
         
 class ContractMaintenanceServices(ModelSQL):