diff --git a/README.md b/README.md
index ffdd550..596a589 100644
--- a/README.md
+++ b/README.md
@@ -6,3 +6,14 @@ Squid helper handling squidguard blacklists written in python
 * Usable as an external acl plugin of squid
 * Written because of poor developpement on squidguard and bad support of blacklists files using squid3
 * Tested on Debian 8 / python 2.7.9
+
+## Usage
+
+Add this configuration to squid.conf :
+```
+external_acl_type urlblacklist_lookup ttl=5 %URI /usr/bin/python /usr/local/blacklists/py-squid-blacklists.py
+...
+acl urlblacklist external urlblacklist_lookup
+...
+http_access deny urlblacklist
+```