diff --git a/README.md b/README.md
index 09c45dab..e9df82f0 100644
--- a/README.md
+++ b/README.md
@@ -104,6 +104,11 @@ calling the `emogrify` method:
   being affected by emogrification.
 
 
+## Requirements
+
+* PHP >= 5.4 or HHVM
+
+
 ## Installing with Composer
 
 Download the [`composer.phar`](https://getcomposer.org/composer.phar) locally