Police say there have been 10 residential break-ins since June in the area bounded by Jane Street to the west, Keele Street to the east, Lawrence Avenue to the south and Highway 401 to the north.
All of the victims have been women in their 70s and 80s, most of them of Italian descent.
"The persons responsible for this cowardly act are preying on seniors and invaded their homes for personal gain," said Det.-Sgt. Colin Greenaway.
Police say a man and a woman enter the homes while the residents are working in their yards, and take cash and jewelery.
Witnesses describe the man as white, with a dark-olive complexion, between 45-55 years of age, with a heavy build and a slight accent.
The woman is described as white, with an olive complexion, approximately 50 years old and 5'1" to 5'5" tall. Witnesses say she has a heavy build, long dark hair and a hawk-shaped nose.
Greenaway said he believes the suspects are targeting seniors' homes for a reason.
"I think that it's easier for them to get away and if they are confronted — which they have been in some of these cases — they can make good their escape much easier," he said Tuesday.
Police are asking for anyone who may have been approached by the suspects or may have witnessed a stranger in their backyard to contact police at 416-808-1200 or Crime Stoppers at 416-222-TIPS (8477).