His owners, Hugh and Kathy Chisholm, said Stan was euthanized on Sunday after a battle with terminal cancer.
The black and white cat made headlines with a campaign to be the mayor of Halifax in 2012. Both daytime television host Ellen DeGeneres and CNN host Anderson Cooper endorsed the feline.
His name was never actually on the ballot since regulations require all candidates to have birth certificates.
The Chisholms put their pet forward in order to highlight the need to spay and neuter the feline population in Halifax. Halifax has laws in place to ensure dogs are spayed and neutered, but no such legislation exists for cats. All the money raised by Stan's campaign was spent fixing cats.
Stan's brother, Earl Gray, is continuing the spay and neuter campaign with a run for premier in the provincial election.