Appending query parameters to a URL is a very common need. However, there's nothing in urllib.parse (and older urlparse) that caters for that need. Therefore, I propose adding the following to 2.7 and 3.1 in the respective libs: def add_query_params(url, **params): """ Adds additional query parameters to the given url, preserving original parameters. Usage: >>> add_query_params('http://foo.com', a='b') 'http://foo.com?a=b' >>> add_query_params('http://foo.com?a=b', b='c', d='q') 'http://foo.com?a=b&b=c&d=q' The real implementation should be more strict, e.g. raise on the following: >>> add_query_params('http://foo.com?a=b', a='b') 'http://foo.com?a=b&a=b' """ if not params: return url encoded = urllib.urlencode(params) url = urlparse.urlparse(url) return urlparse.urlunparse((url.scheme, url.netloc, url.path, url.params, (encoded if not url.query else url.query + '&' + encoded), url.fragment))