diff --git a/graphene/contrib/django/converter.py b/graphene/contrib/django/converter.py
index 65ad8237..951af2ad 100644
--- a/graphene/contrib/django/converter.py
+++ b/graphene/contrib/django/converter.py
@@ -1,4 +1,5 @@
 from django.db import models
+from django.utils.encoding import force_text
 
 from ...core.classtypes.enum import Enum
 from ...core.types.custom_scalars import DateTime, JSONString
@@ -14,7 +15,7 @@ singledispatch = import_single_dispatch()
 
 def convert_choices(choices):
     for value, name in choices:
-        yield to_const(name), value
+        yield to_const(force_text(name)), value
 
 
 def convert_django_field_with_choices(field):
diff --git a/graphene/utils/str_converters.py b/graphene/utils/str_converters.py
index d3a58e6c..ae8ceffe 100644
--- a/graphene/utils/str_converters.py
+++ b/graphene/utils/str_converters.py
@@ -18,4 +18,4 @@ def to_snake_case(name):
 
 
 def to_const(string):
-    return re.sub('[\W|^]+', '_', string.format()).upper()
+    return re.sub('[\W|^]+', '_', string).upper()