diff --git a/node.gyp b/node.gyp
index d631754039..19fa54b10b 100644
--- a/node.gyp
+++ b/node.gyp
@@ -165,6 +165,7 @@
           'sources': [
             'src/node_signal_watcher.cc',
             'src/node_stat_watcher.cc',
+            'src/node_io_watcher.cc',
           ]
         }],
         [ 'OS=="mac"', {
diff --git a/src/node.cc b/src/node.cc
index 31f4633fd9..377fbe64ab 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -70,6 +70,9 @@ typedef int mode_t;
 
 #include "platform.h"
 #include <node_buffer.h>
+#ifdef __POSIX__
+# include <node_io_watcher.h>
+#endif
 #include <node_file.h>
 #include <node_http_parser.h>
 #ifdef __POSIX__
@@ -1887,6 +1890,13 @@ static Handle<Value> Binding(const Arguments& args) {
     DefineConstants(exports);
     binding_cache->Set(module, exports);
 
+#ifdef __POSIX__
+  } else if (!strcmp(*module_v, "io_watcher")) {
+    exports = Object::New();
+    IOWatcher::Initialize(exports);
+    binding_cache->Set(module, exports);
+#endif
+
   } else if (!strcmp(*module_v, "natives")) {
     exports = Object::New();
     DefineJavaScript(exports);
diff --git a/src/node_io_watcher.cc b/src/node_io_watcher.cc
new file mode 100644
index 0000000000..4854a8fa9a
--- /dev/null
+++ b/src/node_io_watcher.cc
@@ -0,0 +1,168 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#include <node_io_watcher.h>
+
+#include <node.h>
+#include <v8.h>
+
+#include <assert.h>
+
+namespace node {
+
+using namespace v8;
+
+Persistent<FunctionTemplate> IOWatcher::constructor_template;
+Persistent<String> callback_symbol;
+
+
+void IOWatcher::Initialize(Handle<Object> target) {
+  HandleScope scope;
+
+  Local<FunctionTemplate> t = FunctionTemplate::New(IOWatcher::New);
+  constructor_template = Persistent<FunctionTemplate>::New(t);
+  constructor_template->InstanceTemplate()->SetInternalFieldCount(1);
+  constructor_template->SetClassName(String::NewSymbol("IOWatcher"));
+
+  NODE_SET_PROTOTYPE_METHOD(constructor_template, "start", IOWatcher::Start);
+  NODE_SET_PROTOTYPE_METHOD(constructor_template, "stop", IOWatcher::Stop);
+  NODE_SET_PROTOTYPE_METHOD(constructor_template, "set", IOWatcher::Set);
+
+  target->Set(String::NewSymbol("IOWatcher"), constructor_template->GetFunction());
+
+  callback_symbol = NODE_PSYMBOL("callback");
+}
+
+
+void IOWatcher::Callback(EV_P_ ev_io *w, int revents) {
+  IOWatcher *io = static_cast<IOWatcher*>(w->data);
+  assert(w == &io->watcher_);
+  HandleScope scope;
+
+  Local<Value> callback_v = io->handle_->Get(callback_symbol);
+  if (!callback_v->IsFunction()) {
+    io->Stop();
+    return;
+  }
+
+  Local<Function> callback = Local<Function>::Cast(callback_v);
+
+  TryCatch try_catch;
+
+  Local<Value> argv[2];
+  argv[0] = Local<Value>::New(revents & EV_READ ? True() : False());
+  argv[1] = Local<Value>::New(revents & EV_WRITE ? True() : False());
+
+  callback->Call(io->handle_, 2, argv);
+
+  if (try_catch.HasCaught()) {
+    FatalException(try_catch);
+  }
+}
+
+
+//
+//  var io = new process.IOWatcher();
+//  process.callback = function (readable, writable) { ... };
+//  io.set(fd, true, false);
+//  io.start();
+//
+Handle<Value> IOWatcher::New(const Arguments& args) {
+  if (!args.IsConstructCall()) {
+    return FromConstructorTemplate(constructor_template, args);
+  }
+
+  HandleScope scope;
+  IOWatcher *s = new IOWatcher();
+  s->Wrap(args.This());
+  return args.This();
+}
+
+
+Handle<Value> IOWatcher::Start(const Arguments& args) {
+  HandleScope scope;
+  IOWatcher *io = ObjectWrap::Unwrap<IOWatcher>(args.Holder());
+  io->Start();
+  return Undefined();
+}
+
+
+Handle<Value> IOWatcher::Stop(const Arguments& args) {
+  HandleScope scope;
+  IOWatcher *io = ObjectWrap::Unwrap<IOWatcher>(args.Holder());
+  io->Stop();
+  return Undefined();
+}
+
+
+void IOWatcher::Start() {
+  if (!ev_is_active(&watcher_)) {
+    ev_io_start(EV_DEFAULT_UC_ &watcher_);
+    Ref();
+  }
+}
+
+
+void IOWatcher::Stop() {
+  if (ev_is_active(&watcher_)) {
+    ev_io_stop(EV_DEFAULT_UC_ &watcher_);
+    Unref();
+  }
+}
+
+
+Handle<Value> IOWatcher::Set(const Arguments& args) {
+  HandleScope scope;
+
+  IOWatcher *io = ObjectWrap::Unwrap<IOWatcher>(args.Holder());
+
+  if (!args[0]->IsInt32()) {
+    return ThrowException(Exception::TypeError(
+          String::New("First arg should be a file descriptor.")));
+  }
+
+  int fd = args[0]->Int32Value();
+
+  if (!args[1]->IsBoolean()) {
+    return ThrowException(Exception::TypeError(
+          String::New("Second arg should boolean (readable).")));
+  }
+
+  int events = 0;
+
+  if (args[1]->IsTrue()) events |= EV_READ;
+
+  if (!args[2]->IsBoolean()) {
+    return ThrowException(Exception::TypeError(
+          String::New("Third arg should boolean (writable).")));
+  }
+
+  if (args[2]->IsTrue()) events |= EV_WRITE;
+
+  assert(!io->watcher_.active);
+  ev_io_set(&io->watcher_, fd, events);
+
+  return Undefined();
+}
+
+
+
+}  // namespace node
diff --git a/src/node_io_watcher.h b/src/node_io_watcher.h
new file mode 100644
index 0000000000..81014feb39
--- /dev/null
+++ b/src/node_io_watcher.h
@@ -0,0 +1,64 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#ifndef NODE_IO_H_
+#define NODE_IO_H_
+
+#include <node_object_wrap.h>
+#include <uv-private/ev.h>
+
+namespace node {
+
+class IOWatcher : ObjectWrap {
+ public:
+  static void Initialize(v8::Handle<v8::Object> target);
+
+ protected:
+  static v8::Persistent<v8::FunctionTemplate> constructor_template;
+
+  IOWatcher() : ObjectWrap() {
+    ev_init(&watcher_, IOWatcher::Callback);
+    watcher_.data = this;
+  }
+
+  ~IOWatcher() {
+    ev_io_stop(EV_DEFAULT_UC_ &watcher_);
+    assert(!ev_is_active(&watcher_));
+    assert(!ev_is_pending(&watcher_));
+  }
+
+  static v8::Handle<v8::Value> New(const v8::Arguments& args);
+  static v8::Handle<v8::Value> Start(const v8::Arguments& args);
+  static v8::Handle<v8::Value> Stop(const v8::Arguments& args);
+  static v8::Handle<v8::Value> Set(const v8::Arguments& args);
+
+ private:
+  static void Callback(EV_P_ ev_io *watcher, int revents);
+
+  void Start();
+  void Stop();
+
+  ev_io watcher_;
+};
+
+}  // namespace node
+#endif  // NODE_IO_H_
+
diff --git a/wscript b/wscript
index 006b0d95ea..51bde44b71 100644
--- a/wscript
+++ b/wscript
@@ -892,6 +892,7 @@ def build(bld):
   if not sys.platform.startswith("win32"):
     node.source += " src/node_signal_watcher.cc "
     node.source += " src/node_stat_watcher.cc "
+    node.source += " src/node_io_watcher.cc "
 
   node.source += bld.env["PLATFORM_FILE"]
   if not product_type_is_lib: