diff --git a/docs/using.rst b/docs/using.rst
index 441bf1623..d5b008670 100644
--- a/docs/using.rst
+++ b/docs/using.rst
@@ -24,7 +24,8 @@ Ubuntu
 ::
 
     sudo apt-get install python python-setuptools python-virtualenv python-dev \
-                 gcc swig dialog libaugeas0 libssl-dev ca-certificates
+                 gcc swig dialog libaugeas0 libssl-dev libffi-dev \
+                 ca-certificates
 
 
 Mac OSX