An agreement was reached Monday with Ralphs, Albertsons and Vons just as those workers were ready to walk off their jobs. Details of the agreement have not released.
Workers will get their first look at the deal when they cast their ballots on Friday and Saturday.
Union officials say the proposed contract addresses the workers' primary concern, which was health coverage. Grocery workers have been working without a contract since March.
A 141-day lockout in 2003-04 cost the stores an estimated $1.5 billion.