diff --git a/README.md b/README.md
index f0bf5cc..6dcfd78 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@ Decorators using lodash functions. View the [API docs](https://steelsojka.github
 
 
 - [Install](#install)
+  - [Polyfills](#polyfills)
 - [Usage](#usage)
   - [Decorators](#decorators)
     - [Example](#example)
@@ -40,6 +41,10 @@ Decorators using lodash functions. View the [API docs](https://steelsojka.github
 
 `npm install --save lodash lodash-decorators`
 
+### Polyfills
+
+This library requires `Map` to be available globally. If `Map` is not supported in your environment then use a polyfill.
+
 ## Usage
 
 For more in depth documentation please visit [Lodash](http://lodash.com/docs)