Index: django/newforms/fields.py
===================================================================
--- django/newforms/fields.py	(revision 6678)
+++ django/newforms/fields.py	(working copy)
@@ -542,6 +542,8 @@
         # will submit for False.
         if value == '0':
             return False
+        if self.required and not value:
+            raise ValidationError(self.error_messages['required'])
         return bool(value)
 
 class NullBooleanField(BooleanField):