diff --git a/README.md b/README.md
index 0212500..c5c8954 100644
--- a/README.md
+++ b/README.md
@@ -71,6 +71,7 @@ b.on('css stream', function (css) {
 - `after`:  optional array of postcss plugins to run after the required css-modules core plugins are run.
 - `generateScopedName`: (API only) a function to override the default behaviour of creating locally scoped classnames.
 - `global`: optional boolean. Set to `true` if you want `css-modulesify` to apply to `node_modules` as well as local files. You can read more about it in the [browserify docs](https://github.com/substack/node-browserify/#btransformtr-opts).
+- `filePattern`: optional regular expression string to specify css file names. (default: `\.css$`)
 
 ### Events
 - `b.on('css stream', callback)` The callback is called with a readable stream containing the compiled CSS. You can write this to a file.
diff --git a/cmify.js b/cmify.js
index 5247b86..1ad8294 100644
--- a/cmify.js
+++ b/cmify.js
@@ -10,14 +10,14 @@ function Cmify(filename, opts) {
 
   stream.Transform.call(this);
 
-  this.cssExt = /\.css$/;
+  this.cssFilePattern = new RegExp(opts.cssFilePattern || '\.css$');
   this._data = "";
   this._filename = filename;
   this._cssOutFilename = opts.cssOutFilename;
 }
 
 Cmify.prototype.isCssFile = function (filename) {
-  return this.cssExt.test(filename)
+  return this.cssFilePattern.test(filename)
 }
 
 Cmify.prototype._transform = function (buf, enc, callback) {
diff --git a/index.js b/index.js
index 93172bb..ddf48c8 100644
--- a/index.js
+++ b/index.js
@@ -101,6 +101,7 @@ module.exports = function (browserify, options) {
   var cssOutFilename = options.output || options.o;
   var jsonOutFilename = options.json || options.jsonOutput;
   transformOpts.cssOutFilename = cssOutFilename;
+  transformOpts.cssFilePattern = options.filePattern;
 
   // PostCSS plugins passed to FileSystemLoader
   var plugins = options.use || options.u;