diff --git a/lib/less/source-map-output.js b/lib/less/source-map-output.js
index 8d2b7c6e..821cfc9f 100644
--- a/lib/less/source-map-output.js
+++ b/lib/less/source-map-output.js
@@ -80,11 +80,11 @@
             this._writeSourceMap(JSON.stringify(this._sourceMapGenerator.toJSON()));
 
             if (this._sourceMapFilename) {
-                this._css.push("/*# sourceMappingURL=" + this._sourceMapRootpath + this._sourceMapFilename + " */");
+                this._css.push("/*# sourceMappingURL=" + this.normalizeFilename(this._sourceMapFilename) + " */");
             }
         }
 
         return this._css.join('');
     };
 
-})(require('./tree'));
\ No newline at end of file
+})(require('./tree'));