Niagara police now say five people were shot outside the L8 nightclub in Thorold.
It happened early Sunday morning about 4:45 on Lundy's Lane.
Police initially said three people were injured and taken to hospital with non-life threatening injuries.
A news release issued Sunday night says they've identified two additional victims.
They were also treated in hospital for non-life threatening injuries.
Police say the victims were four males and one female.
Several vehicles in the parking lot were also damaged during the incident.
Police say the shots were fired from a vehicle leaving the area after the first night of the scheduled two-night Full Moon Party had ended at about 4 a.m.
They are searching for two suspects who fled in a dark-coloured sedan.
Highway 20 remains closed between Highway 58 and Thorold Townline Road while officers continue this investigation.