The Irving, Texas, company said a nationwide strike crippled its ability to make and deliver its products, which also include Ding Dongs, Ho Ho's and Home Pride bread.
Hostess suspended bakery operations at all its factories and said its stores will remain open for several days to sell already-baked products.
The company had warned employees that it would file a motion in U.S. Bankruptcy Court to unwind its business and sell assets if plant operations didn't return to normal levels by Thursday evening. The privately held company filed for Chapter 11 protection in January, its second trip through bankruptcy court in less than a decade.
"Many people have worked incredibly long and hard to keep this from happening, but now Hostess Brands has no other alternative than to begin the process of winding down and preparing for the sale of our iconic brands," CEO Gregory F. Rayburn said in a letter to employees posted on the company website.
He added that all employees will eventually lose their jobs, "some sooner than others."
"Unfortunately, because we are in bankruptcy, there are severe limits on the assistance the (company) can offer you at this time," Rayburn wrote.
Thousands of members of the Bakery, Confectionery, Tobacco Workers and Grain Millers International Union went on strike last week after rejecting in September a contract offer that cut wages and benefits. Hostess said Friday the company is unprofitable "under its current cost structure, much of which is determined by union wages and pension costs."
A union representative did not immediately return a call from The Associated Press seeking comment on the company's announcement.
Hostess has said that production at about a dozen of the company's 33 plants has been seriously affected by the strike. Three plants were closed earlier this week.
Hostess had already reached a contract agreement with its largest union, the International Brotherhood of Teamsters.
The company, founded in 1930, was fighting battles beyond labor costs. Competition is increasing in the snack space and Americans are increasingly conscious about healthy eating. Hostess also makes Dolly Madison, Drake's and Nature's Pride snacks.
Hostess shutdown to be felt in Northeast Philadelphia
As the sun set Friday evening, the number of striking workers holding out on the picket line began to dwindle. Reality is sinking in. Hostess is shutting down and thousands of Hostess workers nationwide have lost their jobs.
Workers on the picket lines outside the Northeast Philadelphia Hostess plant got word Friday morning.
The company is stopping operations and selling off its brands. Nearly 18,500 workers will lose their jobs nationwide, including hundreds at the Northeast Philadelphia location.
"It wasn't the union members that did this, it was the corporate greed," said Wayne Walker.
In January, Hostess filed for bankruptcy for the second time since 2004. Last Saturday, the union representing the company's bakers went on strike to protest wage and benefit cuts in a contract approved by a bankruptcy judge.
"We didn't make that much. We didn't make that much, and they took it away. We didn't have anything. They took everything from us. There was nothing else to take," said Chief Steward Don Devlin.
Hostess gave striking workers until 5:00 p.m. Thursday to return to the jobs. When that didn't happen, the CEO Gregory Rayburn put out a letter Friday morning telling them: "We deeply regret taking this action, but we simply cannot continue to operate without the ability to produce or deliver our products."
Workers were allowed to retrieve personal belongings before the gates were locked.
"There's nothing running, just people with their heads down; what few workers are in there," said Warren Starkus.
Many are hoping another company will buy hostess and hire them back.
"We just thought enough was enough," said Gary Duranceau. "We're hoping down the road somebody buys us and we'll be up and going again."
"There's life after Wonder Bread. We'll survive," said Devlin.
But even if another company buys the Hostess brands, there is no guarantee the workforce would be rehired.