diff --git a/formly/models.py b/formly/models.py
index 74f4b0f..f74b044 100644
--- a/formly/models.py
+++ b/formly/models.py
@@ -373,6 +373,8 @@ def answer_value(self):
     def answer_display(self):
         val = self.answer_value()
         if val and self.question.needs_choices:
+            if self.question.field_type == Field.CHECKBOX_FIELD:
+                return u", ".join([unicode(FieldChoice.objects.get(pk=int(v))) for v in val])
             return FieldChoice.objects.get(pk=int(val))
         return val