Police say the men, in their sixties and seventies, were arrested Friday as a result of a four month investigation.
At least one suspect is a resident of the building where the suspicious package was found.
The Montreal police bomb squad detonated the package containing an explosive substance early Sunday morning.
Police evacuated the social housing complex on Coleraine Street in southwest Montreal Saturday night at 9:30 p.m.
The building's 40 residents were sheltered in a bus provided by Montreal's fire department.
Explosives technicians took nearly ten hours to neutralize the package, which police said turned out to contain an explosive device.
“When the bomb techs arrived at the scene they admitted the level of risk was very high and at that point they started to neutralize,” said Montreal police spokesman Const. Simon Delorme.
Delorme said technicians performed two controlled detonations, exploding the package in the second operation.
Delorme said investigators collected the material from the package and arson experts will analyze it further this week.
The suspects will appear in court Monday to face charges.