diff --git a/lib/less/to-css-visitor.js b/lib/less/to-css-visitor.js
index 868cb0f4..03994a90 100644
--- a/lib/less/to-css-visitor.js
+++ b/lib/less/to-css-visitor.js
@@ -111,6 +111,8 @@
                 }
                 visitArgs.visitDeeper = false;
 
+                this._removeDuplicateRules(rulesetNode.rules);
+
                 // now decide whether we keep the ruleset
                 if (rulesetNode.rules.length > 0 && rulesetNode.paths.length > 0) {
                     rulesets.splice(0, 0, rulesetNode);
@@ -126,6 +128,31 @@
                 return rulesets[0];
             }
             return rulesets;
+        },
+
+        _removeDuplicateRules: function(rules) {
+            // remove duplicates
+            var ruleCache = {},
+                ruleList, rule, i;
+            for(i = rules.length - 1; i >= 0 ; i--) {
+                rule = rules[i];
+                if (rule instanceof tree.Rule) {
+                    if (!ruleCache[rule.name]) {
+                        ruleCache[rule.name] = rule;
+                    } else {
+                        ruleList = ruleCache[rule.name];
+                        if (ruleList instanceof tree.Rule) {
+                            ruleList = ruleCache[rule.name] = [ruleCache[rule.name].toCSS(this._env)];
+                        }
+                        var ruleCSS = rule.toCSS(this._env);
+                        if (ruleList.indexOf(ruleCSS) !== -1) {
+                            rules.splice(i, 1);
+                        } else {
+                            ruleList.push(ruleCSS);
+                        }
+                    }
+                }
+            }
         }
     };
 
diff --git a/lib/less/tree/ruleset.js b/lib/less/tree/ruleset.js
index 92f5540c..f97b6034 100644
--- a/lib/less/tree/ruleset.js
+++ b/lib/less/tree/ruleset.js
@@ -185,7 +185,6 @@ tree.Ruleset.prototype = {
     toCSS: function (env) {
         var i, css = [],   // The CSS output
             rules = [],    // node.Rule instances
-           _rules = [],    //
             rulesets = [], // node.Ruleset instances
             ruleNodes = [],
             rulesetNodes = [],
@@ -245,16 +244,6 @@ tree.Ruleset.prototype = {
                 }).join(env.compress ? ',' : (',\n' + tabSetStr));
 
             if (selector) {
-                //TODO need to do this in the toCSS visitor
-                //only bother doing if compression is on?
-                // Remove duplicates
-                for (var i = rules.length - 1; i >= 0; i--) {
-                    if (rules[i].slice(0, 2) === "/*" ||  _rules.indexOf(rules[i]) === -1) {
-                        _rules.unshift(rules[i]);
-                    }
-                }
-                rules = _rules;
-
                 if (debugInfo) {
                     css.push(debugInfo);
                     css.push(tabSetStr);