diff --git a/docs/downloads.md b/docs/downloads.md
index 0888d99f416..accfa3cc36b 100644
--- a/docs/downloads.md
+++ b/docs/downloads.md
@@ -76,6 +76,8 @@ React.renderComponent(...);
 
 If you'd like to use any [add-ons](/react/docs/addons.html), use `var React = require('react/addons');` instead.
 
+**Note:** by default, React will be in development mode. To use React in production mode, set the environment variable `NODE_ENV` to `production`. A minifier that performs dead-code elimination such as [UglifyJS](https://github.com/mishoo/UglifyJS2) is recommended to completely remove the extra code present in development mode.
+
 ## Bower
 
 ```sh
diff --git a/npm-react/README.md b/npm-react/README.md
index e77fe6f0d9c..5821d8f5681 100644
--- a/npm-react/README.md
+++ b/npm-react/README.md
@@ -5,6 +5,9 @@ without also requiring the JSX transformer. This is especially useful for cases
 want to [`browserify`](https://github.com/substack/node-browserify) your module using
 `React`.
 
+**Note:** by default, React will be in development mode. The development version includes extra warnings about common mistakes, whereas the production version includes extra performance optimizations and strips all error messages.
+
+To use React in production mode, set the environment variable `NODE_ENV` to `production`. A minifier that performs dead-code elimination such as [UglifyJS](https://github.com/mishoo/UglifyJS2) is recommended to completely remove the extra code present in development mode.
 
 ## Example Usage