diff --git a/lib/getChildRules.js b/lib/getChildRules.js
index 788978d..9667904 100644
--- a/lib/getChildRules.js
+++ b/lib/getChildRules.js
@@ -41,8 +41,11 @@ function getChildRules(css, parent) {
         name: atRule.name,
         params: atRule.params
       });
-      // Should append even if parent selector
-      if (rule.selector === parent.selector || childRule) {
+      /**
+       * Should append even if parent selector, but make sure the two rules
+       * aren't identical.
+       */
+      if ((rule.selector === parent.selector || childRule) && _postcss2.default.parse(rule).toString() !== _postcss2.default.parse(parent).toString()) {
         var clone = rule.clone();
         criticalAtRule.append(clone);
         result.push(criticalAtRule);
diff --git a/package.json b/package.json
index 6190fbe..79466c8 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "postcss-critical-css",
-  "version": "2.1.4",
+  "version": "2.1.5",
   "description": "Generate critical CSS using PostCSS",
   "main": "index.js",
   "repository": {
diff --git a/src/getChildRules.js b/src/getChildRules.js
index c6126f7..a5b359e 100644
--- a/src/getChildRules.js
+++ b/src/getChildRules.js
@@ -31,8 +31,14 @@ export function getChildRules (css: Object, parent: Object): Array<Object> {
         name: atRule.name,
         params: atRule.params
       })
-      // Should append even if parent selector
-      if (rule.selector === parent.selector || childRule) {
+      /**
+       * Should append even if parent selector, but make sure the two rules
+       * aren't identical.
+       */
+      if (
+        (rule.selector === parent.selector || childRule) &&
+        postcss.parse(rule).toString() !== postcss.parse(parent).toString()
+      ) {
         const clone = rule.clone()
         criticalAtRule.append(clone)
         result.push(criticalAtRule)