Police responded to a 911 call from a home in the 600 block of Grenville Avenue around 9 p.m. PT.
Officers found an unresponsive 57-year-old man suffering from severe injuries. He was taken to a local hospital, where he later died.
A second man was also injured but is expected to make a full recovery.
A 49-year-old Victoria man is in police custody in connection with the incident.
Police have released few details but say the Vancouver Island Major Crime Unit and Victoria Police are investigating.