The man, who has not been named, was attacked on Lyndoch Street in Greenock this afternoon.
He was taken to Inverclyde Royal Hospital but died after arriving at hospital.
Officers were called at 1.20pm and are still on the scene.
A Police Scotland spokeswoman said: "Investigations are under way following the death of a man in Lyndoch Street in Greenock.
"Officers were notified a man had been assaulted at 1.20pm.
"The injured man was taken to hospital but died shortly thereafter.
"A post mortem examination will be carried out and inquiries are continuing."