A 37-year-old man suffered severe injuries in what Gardai believe was a serious assault in broad daylight.
Officers in the city are investigating the alleged attack which happened at approximately 2pm on Lower Oliver Plunkett Street last Thursday.
The man was treated at the scene for his injuries and was then rushed to Mercy University Hospital Cork following the incident.
However he passed away in hospital yesterday, authorities said.
A post-mortem is being carried out this afternoon by the Assistant State Pathologist.
The results of the examination will determine the direction of the investigation, a Gardai spokesperson said.
In the meantime, Gardaí are appealing for witnesses to the incident or anyone with information to contact them at Anglesea Street Garda Station on 021 - 4522000, the Garda Confidential Line 1800 666111 or any Garda Station.