diff --git a/Dockerfile b/Dockerfile
index bf93968..49fed7a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,10 @@ MAINTAINER Christian Lück <christian@lueck.tv>
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get update && apt-get install -y \
   nginx git supervisor php5-fpm php5-cli php5-curl php5-gd php5-json \
-  php5-pgsql php5-mysql && apt-get clean
+  php5-pgsql php5-mysql php5-mcrypt && apt-get clean
+
+# enable the mcrypt module
+RUN php5enmod mcrypt
 
 # add ttrss as the only nginx site
 ADD ttrss.nginx.conf /etc/nginx/sites-available/ttrss