Teamsters Local 117 spokesman Paul Zilly says the company accepted the workers' offer to return and the strike ended late Wednesday afternoon.
Zilly says more negotiations are scheduled Dec. 20.
Picket lines went up Tuesday after drivers rejected the company's latest contract offer.
The drivers say they don't make nearly as much as their counterparts at other companies.
The Rhode Island-based company did not immediately respond to an Associated Press request for comment after business hours Wednesday.
The company has said its latest offer included a 10.8 percent wage increase over three years.
United Natural Foods supplies organic foods to independent markets and large grocery store chains.
