Fire officials say the blaze broke out around 4 a.m. PT on the 1000 block of Main Street, next to Bovill Square.
About 50 members of the Smithers Volunteer Fire Department are still on the scene, hosing down hotspots on Main Street.
"This is a tragic loss for two local business owners and for our whole community. We are thankful that the fire is now under control and most importantly that there have been no injuries," said Smithers Mayor Taylor Bachrach in a statement.
B.C. Hydro says about 100 customers lost power this morning, but should have it restored later today.
The cause of the fire is not known yet known and there are no reported injuries.