While retail chains now offer deals online, it appears many still enjoy the ritual of heading to the mall to take part in the frenzy.
The first shopper arrived outside Future Shop on Montreal's Ste. Catherine Street at 1 a.m., 12 hours before the store opened.
Kevin Bergeron, 18, said it was a long, cold night. He hoped the electronics store would give him a prize for being first in line.
"I think I'll buy a TV or some video games, or maybe a laptop," he said. "Whatever has the best deal, that's what I'll take."
Down the street, Sammy Bazizi began waiting outside an H & M clothing store at 11 p.m. on Sunday.
"I'm here for a good reason," said Bazizi, 18. "They give $300 for the first person in line. So it's worth it."
Bazizi, who took breaks in his car during the night to keep warm, said he wasn't even sure if he would buy anything right away.
Crowds were just as thick in downtown Toronto, where eager shoppers staked out spots outside some big chains hours before the doors opened.
Inside the Eaton Centre, lineups to get into the most popular stores stretched more than a dozen long well into the afternoon.
Chris Mason only ventured inside to take his girlfriend out for lunch, but ended up getting sucked in by the sales.
"I definitely got some clothes -- half off, which is pretty sweet," he said.
Still, the savings weren't enough to lure him back next year. Mason said the crowd made him feel claustrophobic.
Some shoppers at a Winnipeg mall got more than they bargained for.
Police and paramedics were called to Polo Park mall around 2:30 p.m. following reports of youths shooting pepper spray into a crowd of shoppers.
Const. Jason Michalyshen said three people were sent to hospital in stable condition. An unknown number of others were affected by the spray, which can cause a burning sensation in the eyes, coughing and trouble breathing. No arrests have been made.
Vancouver's shopping district was packed as well.
One store on Granville Street took a creative approach to luring shoppers inside. Musicians were hired to play in the display window.
"It's a lot of fun," said Chelsea Joelle, a DJ.
"(Shoppers) are kind of dumbfounded that we're performing in the window instead of being merchandise."
The lines outside some stores, however, appeared thinner than in previous years.
Many chains began offering deals online on Christmas Eve, leading some shoppers to buy goods from the comfort of their homes.
Despite the increased emphasis on online sales, many customers still enjoy the ritual of the Boxing Day frenzy, said Thierry Lopez, Quebec's director of marketing at Future Shop.
"A lot of people really like coming in the store, touching the product, and there is a social aspect to it," he said.
Lopez added, though, that "being outside and waiting is maybe not for everybody, so that's why we developed the online sale."
Regardless of where shoppers choose to make their purchases, sales are expected to be up this year.
The Retail Council of Canada estimates there will be a three per cent increase in retail sales this Christmas compared to last year.
_ With reports from Keven Drews in Vancouver, Paola Loriggio in Toronto and Mary Jo Laforest in Edmonton