One of the men is believed to be the crane operator while the other is thought to be a member of the public.
A third man was taken to St Thomas’ hospital with minor injuries, London Ambulance Service said.
The crane was on a building site close to Battersea power station, on the south bank of the river Thames in south London.
It smashed into the end property of a row of flats and shops, leaving a huge crack in the building.
Residents of the block of flats were evacuated following the accident.
It is believed the crane driver and a man in his car behind the shops were killed when it fell.
The Health and Safety Executive (HSE) has launched an investigation.
Dozens of firefighters and police cordoned off the area around the building site where one of the two cranes being used for construction had collapsed.
Locals said there had been concerns over the safety of the machinery so close to houses. Flats were being built on the site of an old school.
Jonathan Cloke (Crane Operator) – Age 37
Michael Alexa – Age 23