diff --git a/lib/cssprocessor.js b/lib/cssprocessor.js
index 5e13b09..6f739dd 100644
--- a/lib/cssprocessor.js
+++ b/lib/cssprocessor.js
@@ -8,7 +8,7 @@
 
 'use strict';
 
-var HTTP_URL_REGEX = /^(https?:\/\/)/i;
+var HTTP_URL_REGEX = /^(https?:)?\/\//i;
 
 var CssProcessor = module.exports = function(fileContent, lineFeed, options) {
 	this.fileContent = fileContent;