Officers were called to a disturbance in the town's Graham Avenue where they discovered the man, believed to be in his 40s, seriously injured.
He died a short time later.
The death is being treated as suspicious and police have appealed for witnesses to come forward.
Officers arrived at the scene at around 1.30am yesterday and detect-ives want anyone who was in the area from midnight onwards to contact them.
A post mortem was to take place to establish the cause of death.
Police cordoned off a block of flats in Graham Avenue with tape and uniformed officers stood guard.
Other officers dressed in white suits could be seen entering the block later.
A window on the second floor was smashed and glass was strewn across the ground.
Detective Inspector Filippo Capaldi, who is leading the invest-igation, is appealing for anyone who was in the Graham Avenue area from around midnight on-wards to come forward.
Anyone with any information which can help officers is asked to call Clydebank CID or the non emergency number 101.
Alternatively, contact Crimestoppers on 0800 555111 where information can be given anonymously.