Toronto police say the break-in occurred at a home in the Richland Crescent and Clumber Road area sometime between 6 a.m. and 7 p.m. on Monday.
Police say "a quantity of property was stolen" from the home, including the ashes.
The ashes were inside a sealed cardboard box, which was contained in a blue bag with a drawstring on it. The logo of the St. John's Dixie Cemetery and Crematorium is on the bag.
Anyone with information about the break-in is asked to contact investigators at 416-808-2200. Information can also be passed on anonymously through Crime Stoppers at 416-222-8477.