diff --git a/lib/getDefinePropertySrc.js b/lib/getDefinePropertySrc.js
index 039f442..9ec4bde 100644
--- a/lib/getDefinePropertySrc.js
+++ b/lib/getDefinePropertySrc.js
@@ -12,7 +12,7 @@ var srcs = {
 
 function getDefinePropertySrc() {
     var src = "if (typeof(module.exports) === 'function' || \n" +
-            "(typeof(module.exports) === 'object' && Object.isExtensible(module.exports))) {\n";
+            "(typeof(module.exports) === 'object' && module.exports !== null && Object.isExtensible(module.exports))) {\n";
 
     src += Object.keys(srcs).reduce(function forEachSrc(preValue, value) {
         return preValue += "Object.defineProperty(module.exports, '" +
diff --git a/testLib/null.js b/testLib/null.js
new file mode 100644
index 0000000..b894a23
--- /dev/null
+++ b/testLib/null.js
@@ -0,0 +1 @@
+module.exports = null;
diff --git a/testLib/sharedTestCases.js b/testLib/sharedTestCases.js
index df9a06a..54e4218 100644
--- a/testLib/sharedTestCases.js
+++ b/testLib/sharedTestCases.js
@@ -220,12 +220,18 @@ describe("rewire " + (typeof testEnv === "undefined"? "(node)": "(" + testEnv +
         expect(rewired.__get__("someVar")).to.be("hello");
     });
 
-    it("should not be a problem to have a module that exports a primitive", function() {
+    it("should not be a problem to have a module that exports a boolean", function() {
         expect(function() {
             var rewired = rewire("./boolean.js");
         }).to.not.throwException();
     });
 
+    it("should not be a problem to have a module that exports null", function() {
+        expect(function() {
+            var rewired = rewire("./null.js");
+        }).to.not.throwException();
+    });
+
     it("should not be a problem to have a module that exports a sealed object", function() {
         expect(function() {
             var rewired = rewire("./sealedObject.js");