Representatives of the National Education Association of New York voted Saturday to merge with New York State United Teachers union, the state's largest teachers union.
The state NEA has about 35,000 members, while NYSUT has about 525,000. The two unions had been merged from 1972-76.
NEA spokesman Bernie Mulligan said delegates voted 398-111 at the group's annual convention to join forces with NYSUT.
The two unions plan to work on a joint constitution and hope to be a single union by September 2006, Mulligan said.
NEA President Robin Rapaport said it was important for public school teachers, community college professors and other school employees to have a "combined voice for public education in New York."
The state NEA is part of the National Education Association, the largest public employee organization in the United States. NYSUT is affiliated with the American Federation of Teachers.
Also Saturday, the NEA delegates endorsed state Attorney General Eliot Spitzer, a Democrat, for governor in 2006.