Francis Stuart (Stu) Filbey, 60, president of the American Postal Workers Union, AFL-CIO, died of cancer Tuesday at Georgetown University Hospital.

He had served in that position since 1971 when the APWU was formed with the merger of five postal unions. With nearly 300,000 members, it is the world's largest postal union.

Mr. Filbey had been active in union affairs since 1926, when he became a postal clerk in Baltimore. Born in Wrightsville, Pa., he had grown up in Baltimore.

When he became a postal clerk, he joined the Baltimore local of the old National Federation of Post Office Clerks, serving as an officer for more than 20 years, nine of them as president.

During the same time, Mr. Filbey also was president of the Baltimore Labor Council of AFL-CIO unions for three years and president of the Baltimore Federation of Labor, AFL-CIO, for five years.

In 1961, the National Federation of Post Office Clerks and the National Postal Transport Union merged to become the United Federation of Postal Clerks, AFL-CIO.

A year later, Mr. Filbey moved to Washington after he was elected national administrative aide of the new UFPC. He became its president in 1969.

While his achievements as a postal workers' leader were numerous, he believed his greatest achievement to be the creation of the American Postal Workers Union. He was considered its architect.

Besides the United Federation of Postal Clerks, the APWU was made up of the National Postal Union, the National Association of Post Office and General Service Maintenance Employees, the National Federation of Post Office Motor Vehicles Employees and the National Association of Special Delivery Messengers.

During his years as president, Mr. Filbey led in negotiating the first three contracts ever concluded between postal management and labor.

Under those contracts, negotiated between July, 1971, and July, 1975, average postal worker wages were increased by more than 4,300 per annum across the board, to counting cost-of-living raises. Fringe benefits were markedly improved. Mr. Filbey considered to most important to be a no-layoff clause.

In 1974, he was elected a vice president of the AFL-CIO executive council. Last year, he became secretary of the powerful public employees division of the AFL-CIO.

Mr. Filbey faced one of his biggest problems in 1970, while he was president of the United Federation of Postal Clerks, then the largest union: the nation's postal workers went on strike.

He maintained that it was an "illegal wildcat strike and under law cannot be supported." But he also made clear that the public should know that the work stoppage was "the bitter fruit of low wages and intolerable working conditions to which the present and previous administrations have been to long insensitive."

As a result, the Nixon administration for the first time met the recognized postal unions at the bargaining table. Under the terms of the settlement, wages were raised and a further raise was promised in the then-pending postal reorganization bill that created the U.S. Postal Service.

Mr. Filbey had been a member of the executive committee of Postal Telephone and Telegraph International, which has headquarters in Berne, Switzerland.

A veteran of World War II, he had served in the Army Air Corps and the Army Postal Service.

He is survived by his wife, Evelyn Irene Schminke Filbey, of the home in Silver Spring; a daughter, Elizabeth G. Smith, of Baltimoee, and two grandchildren.