Mercer Union is a Canadian artist-run centre in Toronto, Ontario, established in 1979 to exhibit contemporary art.

[1] Mercer Union was founded in 1979 by artists Michael Balfe, Peter Blendell, Ric Evans, Peter Hill, Jamie Lyons, David MacWilliam, John McKinnon, Robert McNealy, Jaan Poldaas, Renee Van Halm, Joy Walker and Robert Wiens.

The artist's "Shared Propulsion Car," an old Buick stripped of its engine and interior, and then outfitted with a four-seat bicycle pedal and brake system, was confiscated by Toronto police after gallery staff took it for a ride on Queen Street West.

The gallery was raided by the Morality Bureau of the Metropolitan Toronto Police in December 1993, and works by Canadian artist Eli Langer were seized.

The hearing – the first to occur under Canada’s controversial child pornography legislation – examined the question of whether Langer’s depictions of nude children and adults were illegal and should be forfeited, as well as the constitutionality of the law.