diff --git a/lib/exe/css.php b/lib/exe/css.php
index 6c1d607514d3a2c0da391df74e7f704c710fdb93..f7235fd4edd51a2d85ccf6b01e9448d2a11f36c4 100644
--- a/lib/exe/css.php
+++ b/lib/exe/css.php
@@ -166,8 +166,11 @@ function css_out(){
  * @return string
  */
 function css_parseless($css) {
+    global $conf;
+
     $less = new lessc();
     $less->importDir[] = DOKU_INC;
+    $less->setPreserveComments(!$conf['compress']);
 
     if (defined('DOKU_UNITTEST')){
         $less->importDir[] = TMP_DIR;