Yes, but you should start an IOLoop, example from docs:
from tornado import ioloop
from tornado.httpclient import AsyncHTTPClient
def handle_request(response):
if response.error:
print "Error:", response.error
else:
print response.body
ioloop.IOLoop.instance().stop()
http_client = AsyncHTTPClient()
http_client.fetch("http://www.google.com/", handle_request)
ioloop.IOLoop.instance().start()