diff --git a/payroll.py b/payroll.py
index 71d62ed..d3c9f38 100644
--- a/payroll.py
+++ b/payroll.py
@@ -174,7 +174,7 @@ class Payroll(metaclass=PoolMeta):
         self.contract = contract
         contract_end_date = None
         if contract:
-            if not contract.end_date:
+            if not contract.finished_date:
                 end_date = period_end
 
                 if period_start >= contract.start_date: