diff --git a/benchmark/querystring/querystring-parse.js b/benchmark/querystring/querystring-parse.js
new file mode 100644
index 00000000000000..3d88bed07d63da
--- /dev/null
+++ b/benchmark/querystring/querystring-parse.js
@@ -0,0 +1,33 @@
+var common = require('../common.js');
+var querystring = require('querystring');
+var v8 = require('v8');
+
+var bench = common.createBenchmark(main, {
+  type: ['noencode', 'encodemany', 'encodelast'],
+  n: [1e6],
+});
+
+function main(conf) {
+  var type = conf.type;
+  var n = conf.n | 0;
+
+  var inputs = {
+    noencode: 'foo=bar&baz=quux&xyzzy=thud',
+    encodemany: '%66%6F%6F=bar&%62%61%7A=quux&xyzzy=%74h%75d',
+    encodelast: 'foo=bar&baz=quux&xyzzy=thu%64'
+  };
+  var input = inputs[type];
+
+  // Force-optimize querystring.parse() so that the benchmark doesn't get
+  // disrupted by the optimizer kicking in halfway through.
+  for (var name in inputs)
+    querystring.parse(inputs[name]);
+
+  v8.setFlagsFromString('--allow_natives_syntax');
+  eval('%OptimizeFunctionOnNextCall(querystring.parse)');
+
+  bench.start();
+  for (var i = 0; i < n; i += 1)
+    querystring.parse(input);
+  bench.end(n);
+}
diff --git a/benchmark/querystring/querystring-stringify.js b/benchmark/querystring/querystring-stringify.js
new file mode 100644
index 00000000000000..d4bb95c21e5af4
--- /dev/null
+++ b/benchmark/querystring/querystring-stringify.js
@@ -0,0 +1,45 @@
+var common = require('../common.js');
+var querystring = require('querystring');
+var v8 = require('v8');
+
+var bench = common.createBenchmark(main, {
+  type: ['noencode', 'encodemany', 'encodelast'],
+  n: [1e6],
+});
+
+function main(conf) {
+  var type = conf.type;
+  var n = conf.n | 0;
+
+  var inputs = {
+    noencode: {
+      foo: 'bar',
+      baz: 'quux',
+      xyzzy: 'thud'
+    },
+    encodemany: {
+      '\u0080\u0083\u0089': 'bar',
+      '\u008C\u008E\u0099': 'quux',
+      xyzzy: '\u00A5q\u00A3r'
+    },
+    encodelast: {
+      foo: 'bar',
+      baz: 'quux',
+      xyzzy: 'thu\u00AC'
+    }
+  };
+  var input = inputs[type];
+
+  // Force-optimize querystring.stringify() so that the benchmark doesn't get
+  // disrupted by the optimizer kicking in halfway through.
+  for (var name in inputs)
+    querystring.stringify(inputs[name]);
+
+  v8.setFlagsFromString('--allow_natives_syntax');
+  eval('%OptimizeFunctionOnNextCall(querystring.stringify)');
+
+  bench.start();
+  for (var i = 0; i < n; i += 1)
+    querystring.stringify(input);
+  bench.end(n);
+}