diff --git a/index.js b/index.js
index b599404..524a2a6 100644
--- a/index.js
+++ b/index.js
@@ -69,6 +69,8 @@ function AssertionError (message, _props, ssf) {
   ssf = ssf || arguments.callee;
   if (ssf && Error.captureStackTrace) {
     Error.captureStackTrace(this, ssf);
+  } else {
+    this.stack = new Error().stack;
   }
 }
 
diff --git a/test/test.js b/test/test.js
index edbe6a7..c696e0f 100644
--- a/test/test.js
+++ b/test/test.js
@@ -13,6 +13,10 @@ suite(function (test, assert) {
     assert(empty.message === 'Unspecified AssertionError', 'w/o err.message');
   });
 
+  test('stack', function() {
+    assert(typeof new AssertionError().stack === 'string');
+  });
+
   test('custom properties', function () {
     var err = new AssertionError('good message', {
         name: 'ShouldNotExist'