diff --git a/example/example/app/models.py b/example/example/app/models.py
index e4f6504..a0a915a 100644
--- a/example/example/app/models.py
+++ b/example/example/app/models.py
@@ -42,7 +42,9 @@ TAGS_CHOICES = (
 class Book(models.Model):
     title = models.CharField(max_length=200)
     categories = MultiSelectField(choices=CATEGORY_CHOICES,
-                                  max_choices=3)
+                                  max_choices=3,
+                                  #default='1,5',
+                                  default=1)
     tags = MultiSelectField(choices=TAGS_CHOICES,
                             null=True, blank=True)
 
diff --git a/src/multiselectfield/db/fields.py b/src/multiselectfield/db/fields.py
index 6a39f5e..ba19a27 100644
--- a/src/multiselectfield/db/fields.py
+++ b/src/multiselectfield/db/fields.py
@@ -82,7 +82,12 @@ class MultiSelectField(models.CharField):
                     raise exceptions.ValidationError(self.error_messages['invalid_choice'] % {"value": value})
                 else:
                     raise exceptions.ValidationError(self.error_messages['invalid_choice'] % value)
-        return
+
+    def get_default(self):
+        default = super(MultiSelectField, self).get_default()
+        if isinstance(default, int):
+            default = string_type(default)
+        return default
 
     def formfield(self, **kwargs):
         defaults = {'required': not self.blank,