diff --git a/lib/less/tree/comment.js b/lib/less/tree/comment.js
index <HASH>..<HASH> 100644
--- a/lib/less/tree/comment.js
+++ b/lib/less/tree/comment.js
@@ -8,7 +8,9 @@ tree.Comment = function (value, silent, index, currentFileInfo) {
 tree.Comment.prototype = {
     type: "Comment",
     toCSS: function (env) {
-        return (env.compress || (this.currentFileInfo && this.currentFileInfo.reference && !this.isReferenced)) ? '' : this.value;
+        var isReference = (this.currentFileInfo && this.currentFileInfo.reference && !this.isReferenced),
+            isCompressed = env.compress && !this.value.match(/^\/\*!/);
+        return (isReference || isCompressed) ? '' : this.value;
     },
     eval: function () { return this; },
     markReferenced: function () {
Improve comments stripping in compress

Ignore comment during compress if starts with exclamation mark