The man was attacked in a petrol station car park at around 9pm last Friday and was pronounced dead this afternoon at Cork University Hospital.
No arrests have been made and an incident room has been set up at Cobh Garda Station.
A post mortem examination will take place tomorrow, the results of which will determine the course of the investigation.
A family liaison officer has been appointed to the man's family.
Garda are appealing for anyone with dash cam footage from the Newtown Road between 8:45pm and 9:15pm to contact them.
