Authorities were still investigating the deaths of the two men, who were both in their 20s.
Police said the two died one day apart and were known to each other. They said that during their investigation of the deaths they found pills that resembled the synthetic drug OxyContin 80.
However, since the drugs are not readily available, police said they believe the pills they found were counterfeit — and may have been lethal.
"Instead of OxyContin, the pills may contain other unknown deadly ingredients," police said in a statement on the case Monday.
A number of agencies are working on the case, including police from the drug enforcement team and the office of the coroner for Saskatchewan.
Police were also warning people about the illicit drugs and the potential danger.
The pills were described as round convex in shape, blue/green in colour with the number 80 stamped on one side and the letters CDN on the other.
Genuine OxyContin is the brand name of a powerful pain killer known as oxycodone. It is an opioid, a synthetic preparation, that can lead to abuse and addiction.
While police in Saskatoon have not identified the lethal ingredient, warnings issued in February by the Canadian Centre on Substance Abuse suggest oxycodone laced with fentanyl may be involved.