Over 110,000 spectators and thousands of athletes celebrated as IOC President Juan Antonio Samaranch declared the Games "the best Olympics ever".
Samaranch, who was overseeing his last Games, asked to be excused his Spanish accent before shouting, "Aussie, Aussie Aussie!" to huge cheers.
"These have been your Games," he told the crowd.
Exceptional
"Athletes of the world - you have given us your very best. Thank you for these exceptional Games.
"I am proud and happy to proclaim that you have presented to the world the best Olympic Games ever. Thank you Sydney, thank you New South Wales, thank you Australia."
The ceremony was the usual mixture of high energy and high camp.
Australian acts from Savage Garden to a re-fronted INXS played from a giant stage at one end of the stadium while various giant inflatables toured the track.
Kylie Minogue performed Abba's 'Dancing Queen' as some of the flavour of Sydney's Mardi Gras came to the Games.
Greek dancers re-enacted an ancient Olympic ceremony while the crowd waved glow-sticks.
Flame
As the Olympic flame was extinguished, 13-year-old Nikki Webster - star of the opening ceremony a long fortnight ago - sang from a podium suspended high above the stadium.
After the Olympic flag had been handed over to delegates from Athens, Australian Yvonne Kenny sang the Olympic anthem.
Samaranch, who has headed the IOC for longer than anyone except Baron de Coubertin, declared the Games closed to groans from the stands before making the traditional declaration.
"I call upon the youth of the world to come together in Athens, Greece, in four years time," he said.