diff --git a/lib/CSSStyleSheet.js b/lib/CSSStyleSheet.js
index 3ec733f..885b3c5 100644
--- a/lib/CSSStyleSheet.js
+++ b/lib/CSSStyleSheet.js
@@ -41,6 +41,7 @@ CSSOM.CSSStyleSheet.prototype.insertRule = function(rule, index) {
 		throw new RangeError("INDEX_SIZE_ERR");
 	}
 	var cssRule = CSSOM.parse(rule).cssRules[0];
+	cssRule.parentStyleSheet = this;
 	this.cssRules.splice(index, 0, cssRule);
 	return index;
 };
diff --git a/spec/CSSStyleSheet.spec.js b/spec/CSSStyleSheet.spec.js
index 01f80ab..828bc6c 100644
--- a/spec/CSSStyleSheet.spec.js
+++ b/spec/CSSStyleSheet.spec.js
@@ -18,5 +18,12 @@ describe('CSSStyleSheet', function() {
 		expect(s.cssRules).toEqual([]);
 	});
 
+	describe('insertRule', function () {
+		it('should correctly set the parent stylesheet', function () {
+			var s = new CSSOM.CSSStyleSheet;
+			s.insertRule("a {color: blue}", 0);
+			expect(s.cssRules[0].parentStyleSheet).toBe(s);
+		});
+	});
 });
 });