The Office and Professional Employees International Union was chartered in 1945 by the American Federation of Labor. At the time of its founding, the membership of the Union numbered 22,000.  The Union now counts 145,000 members and is one of the larger unions in the AFL-CIO. As it moves into its 57th year of chartered existence, the OPEIU has local unions functioning throughout the fifty states, as well as Puerto Rico and the District of Columbia

The Union represents and bargains for both private and public sector professional and semiprofessional workers laboring in most of the major industries in the United States. The OPEIU is also affiliated with a number of state and national professional organizations.

OPEIU members work in industries varied as motion picture industry, banking, insurance, universities, shipping, hospitals and nursing homes, utilities, transportation, manufacturing, paper companies, hotels and many more. They are in positions as varied as computer programmers and operators, engineers, secretaries, nurses, accountants, attorneys, transit supervisors, security guards, bank tellers, administrative aides, quality control personnel, doctors, models, police and others.