Union leaders worked through the 7:10 p.m. Sunday deadline, when workers could have walked off the job.
The agreement, which was reached just before noon, must still be approved by union members before it can go into effect. The vote is expected to take place Saturday.
"Thanks to the unity of our members and the hard work of our negotiating team, we were successful in bargaining an agreement that grocery workers can be proud of," said union negotiators in a statement. "We have attained our most important goal, which was continuing to provide comprehensive health care to the members and their families."
A joint statement by Albertsons, Ralphs and Vons was released Monday afternoon:
"We are pleased to have reached a tentative settlement agreement with the union that continues to preserve good wages, secure pensions and access to quality, affordable health care - while allowing us to be competitive in the marketplace. We appreciate the hard work, support and patience that everyone has shown during the past seven months, and particularly the past few weeks."
Workers could have gone on strike as early at 12:01 a.m., which is when the notice period expired. Sunday night, grocery store workers held a candlelight vigil and a march to show their resolve.
Grocery workers have been working without a contract since March. The main sticking point between stores and unions has been health insurance benefits.
Under a recent offer from supermarkets rejected by union members, workers would pay $9 a week for individual health insurance coverage and $23 a week for a family. For the individual, that's an increase of $2 each week.
It may not sound like much, but it's significant for some workers like Yesleni Avila of the Ralphs store in Riverside.
"I started here making 40 hours a week and then it went down to 25 and now it's 16," she said. "I have a family and a daughter. I've been here since '07, still making minimum wage."
"These stores are doing great, the markets are doing great," said Mike Shimpock from UFCW Local 770. "All we are asking is that they help the people that are helping make those profits. We don't want to inconvenience consumers. We don't want to inconvenience our workers. All we want to do is go to work, pay our rent, take our kids to the doctor if they get sick."
If a strike occurred, many customers would have had to find another place to shop as supermarket executives had planned to close hundreds of stores if there had been a strike. Ralphs announced it would close all of its stores in the event of a strike. Albertsons said it would close about 100 stores, while Vons said its stores would remain open.
"The consumers want to make sure that they can shop where they've gone to on a regular basis," said Los Angeles Mayor Antonio Villaraigosa, who had urged both sides to come to an agreement. "My hope is that both sides - management and labor - will sit down and work this out."
A strike in 2003 lasted 141 days and cost stores and estimated $2 billion. Both sides have said that a strike is not ideal and they hope a compromise is reached.