Miguel Contreras,52, secretary-treasurer of the Los Angeles County Federation of Labor, passed away unexpectedly on May 6.

Miguel, whose parents were migrant farm workers, is widely credited with organizing immigrant labor into a formidable political and economic force in the labor movement. He began his union work with the United Farm Workers, and then served HERE for more than a decade before moving to the Los Angeles County Federation of Labor. Miguel is survived by his wife Maria Elena, and his sons Mario and Michael.

Mr. Contreras began working in the fields of the Central Valley outside Dinuba, Calif., at the age of 5. By age 17, he was handing out grape boycott leaflets at grocery stores for the famous United Farmworkers campaign. He eventually became a strike captain and was sent to Toronto by the labor leader Cesar E. Chavez. He worked with unions in Salinas and San Francisco before the Hotel Employees and Restaurant Employees Union recruited him as a national organizer, taking him to Los Angeles in the late 1980’s.

Mr. Contreras, whose political clout extended from City Hall to Sacramento and beyond, was credited with bringing together the federation’s 345 local unions in recent years to organize workers and pressure employers more effectively.

Contreras was a deal maker who understood power and how to use it behind the scenes, colleagues said, but was at his best at noisy rallies that fired up the rank-and-file for big initiatives.

In lieu of flowers, please send donations to the Miguel Contreras Memorial Fund, c/o Amalgamated Bank – Pasadena Branch, 60 S. Los Robles Ave., Pasadena, CA 91104-3508, 626-432-9900.