The United Food and Commercial Workers on Friday joined the Teamsters and Service Workers in abandoning the AFL-CIO, depriving the labor federation of three of its largest unions and close to $28 million of its estimated $120 million budget.

The departure of the 1.4 million member UFCW from the labor federation means the AFL-CIO (search) is losing more than 4 million of its 13 million members.

Earlier this week, the UFCW joined the Teamsters, Service Employees International Union and Unite Here — a group of textile, restaurant and hotel employees — in boycotting the AFL-CIOving the AFL-CIO. Unite Here is still considering its next step.

During the convention, AFL-CIO President John Sweeney (search) was re-elected to another term and he pledged to make changes to address the woes of organized labor (search). But the departing unions say those changes are insufficient.

"The world has changed and workers' rights and living standards are under attack," UFCW President Joe Hansen said in a letter delivered to Sweeney on Friday. "Tradition and past success are not sufficient to meet the new challenges."

The departure of the unions has frustrated labor federation officials.

"The UFCW leadership decision to leave the AFL-CIO, especially when working people are up against the most powerful, anti-worker corporate and governmental forces in 80 years, is a tragedy for working families," said Lane Windham, spokesperson for the AFL-CIO. "Only union's enemies win when unions split our strength."

The unions breaking away from the AFL-CIO want to commit more money to recruiting new members and complain that the federation has committed too much money and placed too much emphasis on backing political candidates — particularly Democrats.

Hansen of UFCW said during a conference call that his union is healthy financially and that its alliance with the Teamsters and service workers is about cooperation, not money. Hansen said leaving the federation was not about saving money, adding: "I plan to devote as much money as I can to organizing."

Hansen noted that "politics are extremely important. We might be more selective in some ways, searching out politicians who will support workers."

At the same time, he said politicians who support labor will still see "a broad front of support" from unions.

"While our affiliation ends, our commitment to work with the AFL-CIO and unions affiliated with the AFL-CIO on issues and programs where we share common goals remains unchanged," Hansen said in his letter to Sweeney. "I believe our movement is united in our basic principles and values, even if we pursue different strategies."

The departure is part of the biggest rift in organized labor since 1938, when the CIO split from the AFL. Supporters of the breakup note that labor made big gains while the two groups competed.

When the AFL-CIO merged in the 1950s, one of every three private-sector workers belonged to a labor union. Now, less than 8 percent of private-sector workers are unionized.