diff --git a/IPython/html/base/zmqhandlers.py b/IPython/html/base/zmqhandlers.py
index 3b72c86..7eec55b 100644
--- a/IPython/html/base/zmqhandlers.py
+++ b/IPython/html/base/zmqhandlers.py
@@ -202,12 +202,6 @@ class AuthenticatedZMQStreamHandler(ZMQStreamHandler, IPythonHandler):
         Extend this method to add logic that should fire before
         the websocket finishes completing.
         """
-        # Check to see that origin matches host directly, including ports
-        # Tornado 4 already does CORS checking
-        if tornado.version_info[0] < 4:
-            if not self.check_origin(self.get_origin()):
-                raise web.HTTPError(403)
-        
         # authenticate the request before opening the websocket
         if self.get_current_user() is None:
             self.log.warn("Couldn't authenticate WebSocket connection")
@@ -224,10 +218,7 @@ class AuthenticatedZMQStreamHandler(ZMQStreamHandler, IPythonHandler):
         # assign and yield in two step to avoid tornado 3 issues
         res = self.pre_get()
         yield gen.maybe_future(res)
-        # FIXME: only do super get on tornado ≥ 4
-        # tornado 3 has no get, will raise 405
-        if tornado.version_info >= (4,):
-            super(AuthenticatedZMQStreamHandler, self).get(*args, **kwargs)
+        super(AuthenticatedZMQStreamHandler, self).get(*args, **kwargs)
     
     def initialize(self):
         self.log.debug("Initializing websocket connection %s", self.request.path)
@@ -235,12 +226,6 @@ class AuthenticatedZMQStreamHandler(ZMQStreamHandler, IPythonHandler):
     
     def open(self, *args, **kwargs):
         self.log.debug("Opening websocket %s", self.request.path)
-        if tornado.version_info < (4,):
-            try:
-                self.get(*self.open_args, **self.open_kwargs)
-            except web.HTTPError:
-                self.close()
-                raise
         
         # start the pinging
         if self.ping_interval > 0:
diff --git a/IPython/html/notebookapp.py b/IPython/html/notebookapp.py
index b6b41bb..f9fb654 100644
--- a/IPython/html/notebookapp.py
+++ b/IPython/html/notebookapp.py
@@ -35,7 +35,7 @@ from zmq.eventloop import ioloop
 ioloop.install()
 
 # check for tornado 3.1.0
-msg = "The IPython Notebook requires tornado >= 3.1.0"
+msg = "The IPython Notebook requires tornado >= 4.0"
 try:
     import tornado
 except ImportError:
@@ -44,7 +44,7 @@ try:
     version_info = tornado.version_info
 except AttributeError:
     raise ImportError(msg + ", but you have < 1.1.0")
-if version_info < (3,1,0):
+if version_info < (4,0):
     raise ImportError(msg + ", but you have %s" % tornado.version)
 
 from tornado import httpserver
diff --git a/IPython/html/terminal/handlers.py b/IPython/html/terminal/handlers.py
index 20e0fa7..bbb8e4a 100644
--- a/IPython/html/terminal/handlers.py
+++ b/IPython/html/terminal/handlers.py
@@ -27,22 +27,9 @@ class TermSocket(terminado.TermSocket, IPythonHandler):
     def get(self, *args, **kwargs):
         if not self.get_current_user():
             raise web.HTTPError(403)
-
-        # FIXME: only do super get on tornado ≥ 4
-        # tornado 3 has no get, will raise 405
-        if tornado.version_info >= (4,):
-            return super(TermSocket, self).get(*args, **kwargs)
+        return super(TermSocket, self).get(*args, **kwargs)
     
     def clear_cookie(self, *args, **kwargs):
         """meaningless for websockets"""
         pass
 
-    def open(self, *args, **kwargs):
-        if tornado.version_info < (4,):
-            try:
-                self.get(*self.open_args, **self.open_kwargs)
-            except web.HTTPError:
-                self.close()
-                raise
-
-        super(TermSocket, self).open(*args, **kwargs)
diff --git a/IPython/testing/iptest.py b/IPython/testing/iptest.py
index 125f9cf..54ac454 100644
--- a/IPython/testing/iptest.py
+++ b/IPython/testing/iptest.py
@@ -132,7 +132,7 @@ have['pymongo'] = test_for('pymongo')
 have['pygments'] = test_for('pygments')
 have['qt'] = test_for('IPython.external.qt')
 have['sqlite3'] = test_for('sqlite3')
-have['tornado'] = test_for('tornado.version_info', (3,1,0), callback=None)
+have['tornado'] = test_for('tornado.version_info', (4,0), callback=None)
 have['jinja2'] = test_for('jinja2')
 have['mistune'] = test_for('mistune')
 have['requests'] = test_for('requests')
diff --git a/setup.py b/setup.py
index 931d216..d4478b3 100755
--- a/setup.py
+++ b/setup.py
@@ -276,7 +276,7 @@ extras_require = dict(
     test = ['nose>=0.10.1', 'requests'],
     terminal = [],
     nbformat = ['jsonschema>=2.0'],
-    notebook = ['tornado>=3.1', 'pyzmq>=2.1.11', 'jinja2', 'pygments', 'mistune>=0.3.1'],
+    notebook = ['tornado>=4.0', 'pyzmq>=2.1.11', 'jinja2', 'pygments', 'mistune>=0.3.1'],
     nbconvert = ['pygments', 'jinja2', 'mistune>=0.3.1']
 )