diff --git a/addons/account_check_writing/report/check_print.py b/addons/account_check_writing/report/check_print.py
index be5feb4662b..af5097cc5ad 100644
--- a/addons/account_check_writing/report/check_print.py
+++ b/addons/account_check_writing/report/check_print.py
@@ -36,7 +36,7 @@ class report_print_check(report_sxw.rml_parse):
         })
 
     def fill_stars(self, amount):
-        if len(amount) < 100:
+        if amount and len(amount) < 100:
             stars = 100 - len(amount)
             return ' '.join([amount,'*'*stars])