The study - conducted by website Badoo - looked at what time most people are online chatting and how long they spend doing so.
It was discovered that people in Cairo tended to be online at 12.45 pm - that's 75 minutes later than in London and three hours later than in New York.
Montevideo in Uruguay came second followed by Beirut in Lebanon, but many metropolises which are thought of as being 24-hour cities were considerably lower.
London was only 17th while Paris was 18th and Rome 27th. New York "the city that never sleeps," also ranked a humiliating 32nd… though people their may have still being out with something better to do than go online.
WORLD’S 10 MOST NOCTURNAL CITIES
Cairo (Egypt)
Montevideo (Uruguay)
Beirut (Lebanon)
Malaga (Spain)
Zaragoza (Spain)
Madrid (Spain)
Barcelona (Spain)
Valencia (Spain)
Seville (Spain)
Buenos Aires (Argentina)
A spokesperson for Badoo said: "Our figures suggest that New Yorkers are climbing into bed at around the time that Cairo residents are preparing to go out."