diff --git a/docs/installation.rst b/docs/installation.rst
index 63555ab..15e88a8 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -7,6 +7,17 @@
 
     $ pip install cryptography
 
+Supported platforms
+-------------------
+
+Currently we test ``cryptography`` on these platforms.
+
+* x86-64 Ubuntu 12.04 LTS
+* x86-64 CentOS 6.4 and CentOS 5
+* x86-64 FreeBSD 9.2 and FreeBSD 10
+* OS X 10.9 and OS X 10.8.5
+* 64-bit Windows Server 2008
+
 On Windows
 ----------