diff --git a/ExistingProjects/Tryton/Installation.mdwn b/ExistingProjects/Tryton/Installation.mdwn
index 62d118368c1e9bd08b7e99576464dff371c2fbaf..34238758ff95b1ab00f46c35f85b46c834f4233a 100644
--- a/ExistingProjects/Tryton/Installation.mdwn
+++ b/ExistingProjects/Tryton/Installation.mdwn
@@ -5,5 +5,5 @@
 ## Tryton installation
 
 1. `sudo apt-get update`
-2. `sudo apt-get install python-pip python-dev libxml2-dev libxslt1-dev`
+2. `sudo apt-get install python-pip python-dev python-gtk2 libxml2-dev libxslt1-dev`
 3. `sudo pip install tryton trytond`