Officers were called to a property in the Gallowhill area shortly before 11pm where they found two men with serious injuries.
One man, aged 53, died at the scene, while a 32-year-old man was rushed to the town's Royal Alexandra Hospital, where staff today described his condition as "serious but stable".
Police cordoned off the flat in Glencairn Road and officers remained at the scene today.
Door-to-door inquiries are being carried out in the area, and police are checking CCTV images.
A post mortem examination will take place in due course.