diff --git a/src/program/forms.py b/src/program/forms.py
index e13d28be..e5d8af16 100644
--- a/src/program/forms.py
+++ b/src/program/forms.py
@@ -29,7 +29,7 @@ class BaseEventProposalForm(forms.ModelForm):
 
     def clean_duration(self):
         duration = self.cleaned_data['duration']
-        if duration < 60 or duration > 180:
+        if not duration or duration < 60 or duration > 180:
             raise forms.ValidationError("Please keep duration between 60 and 180 minutes.")
         return duration