The fire, on the 6200 block of West Cermak Road, began in an apartment unit above Art's Cycling & Fitness, officials said.
The owner of a popular west suburban bike shop vowed to rebuild as he watched the business his father launched decades ago go up in flames.
"I sure hope we will. No reason why we won't," Barry Kerstein, the owner of Art's Cycling & Fitness, said as he watched firefighters tackle the job.
Officials said the fire started in an apartment unit above the shop, on the 6200 block of West Cermak Road in Berwyn. The fire caused the roof of the apartment to collapse, but no injuries were reported as of 7 a.m.
"There's a tenant upstairs, and thank God they're both OK," said Kerstein.
Art Kerstein launched the shop in 1946 as a toy and bike store. Barry Kerstein said he took over the business 20 years ago when his father passed away.
"I'm numb just watching it. It's sickening. I just am watching my life go away," he said.
Cermak Road between South Austin Boulevard and Ridgeland Avenue was closed to early morning traffic while firefighters tended to the blaze. Power and gas service to the area was shut off. Warming buses were brought in to assist the firefighters working on a rotating schedule in cold, windy conditions.