The news averted a walkout that had been threatened for 7 p.m. Monday at QFC, Albertsons, Fred Meyer and Safeway stores in King, Snohomish, Pierce, Kitsap, Mason and Thurston counties.
The team bargaining on behalf of three union locals unanimously recommended that workers approve the agreement, said Tom Geiger, spokesman for United Food and Commercial Workers Local 21.
The grocery stores negotiated through the Allied Employers group.
"We are pleased to announce that we have reached a tentative settlement agreement with the unions that continues to preserve good wages, secure pensions and access to quality, affordable health care for our employees," Scott Powers, Allied Employers vice president, said in an email.
Both sides said details of the proposal would not be released until workers had a chance to review and vote on it. No dates were immediately announced for that vote.
Union locals involved include UFCW 21 and 367 and Teamsters Local 38.
Local 21 president David Schmitz said the agreement is a victory for all workers and thanked customers for their support.
"Our customers gave our members great strength and support," he said. "They told them day after day after day that what's going on here is not right and we'll stand by you. This is not how America should work, and we're going to help you make it work how it should. And our members drew great strength from that."
Issues that had been unresolved after the unions issued a 72-hour strike notice Friday evening included wages, holiday pay and proposed cuts to health care benefits. The two sides have been in talks for more than six months, Geiger has said.
Powers has said the employers wanted a solid pay and benefits package for workers that would allow the companies to be competitive.
In downtown Seattle, a makeshift clock had been counting down the number of hours until a possible strike.