diff --git a/readme.md b/readme.md
index cfea4e34..4a8c6955 100644
--- a/readme.md
+++ b/readme.md
@@ -11,6 +11,7 @@ version < 1.3.0.
 [![Build Status](https://travis-ci.org/Pierre-Sassoulas/django-survey.svg?branch=master)](https://travis-ci.org/Pierre-Sassoulas/django-survey)
 [![Coverage Status](https://coveralls.io/repos/github/Pierre-Sassoulas/django-survey/badge.svg?branch=master)](https://coveralls.io/github/Pierre-Sassoulas/django-survey?branch=master)
 [![PyPI version](https://badge.fury.io/py/django-survey-and-report.svg)](https://badge.fury.io/py/django-survey-and-report)
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
 
 ## Table of contents