Saint John Police Force members were called after shots were fired near Waterloo Street on Sunday morning.
A call came just after 5:00 a.m., and two 25-year-old men were taken to hospital after the incident.
One man has already been released, while the other is being treated for non-life threatening injuries.
Police have taken a man and woman into custody, but have released no further personal details at this time.
The Major Crime and Forensic Unit is investigating.