diff --git a/index.js b/index.js
index 10da346..0f312c4 100644
--- a/index.js
+++ b/index.js
@@ -64,7 +64,7 @@ function compileRoute (route, options) {
               pathParams[key] = values[key]
           }
         } else {
-          queryParams[key] = values[key]
+          if (typeof values[key] !== 'undefined') queryParams[key] = values[key]
         }
       })
 
diff --git a/tests/test.js b/tests/test.js
index 4975c89..9e21968 100644
--- a/tests/test.js
+++ b/tests/test.js
@@ -339,6 +339,17 @@ module.exports = {
         test.done()
       },
 
+      'should not stringify undefined query params': function (test) {
+        var mapper = urlMapper({ query: true })
+
+        test.equal(mapper.stringify('/:foo', {
+          foo: 'bar',
+          bar: undefined
+        }), '/bar')
+
+        test.done()
+      },
+
       'should parse stringified object including params not defined in route': function (test) {
         var mapper = urlMapper({ query: true })
         var object = {