1990 York North federal by-election

A by-election was held in the federal riding of York North in Ontario on December 10, 1990, after the 1988 election of Liberal member of Parliament (MP) Maurizio Bevilacqua was voided by the Supreme Court of Ontario.

In the 1988 federal election, Progressive Conservative candidate Micheal O'Brien was declared the winner for York North following a judicial recount and served 55 days as the MP for the riding. However, a second judicial recount reversed the result, and Bevilacqua was declared elected by a margin of 77 votes, marking the first time in Canadian history that two MPs had been sworn in for the same riding as the result of a single election. In May 1990, the court annulled the result over voting irregularities, the first such ruling since 1957.

Bevilacqua won the ensuing by-election by more than 7,000 votes over the second-place NDP candidate, while the Progressive Conservatives fell to third place. The by-election was held on the same day as another federal by-election in Beauséjour in New Brunswick.