J. Richard Rancourt, 60, the organist at St. Stephen's Martyr Catholic Church in Washington and a former dean of the D.C. chapter of the American Guild of Organists, died Monday at George Washington University Hospital following a heart attack.

Mr. Rancourt had been organist at St. Stephen's since 1959. Before that, he was the organist at St. Peter's Catholic Church. He was a member of the Washington Archdiocesan Liturgical Music Commission. He was the treasurer and finance director for the 1982 convention of the American Guild of Organists, which is to be held here.

A native of Waterville, Maine, Mr. Rancourt graduated from Colby College there in 1942. He served in the Army during World War II and later moved to Washington, where he worked for the Army. In 1950, he earned a master's degree in music at the University of North Carolina.

He then returned to Washington and worked at the Pentagon. For the past 19 years, he had been manager of the sheet music department of Jordan Kitt's Music Company.

His wife, Jane Beatrice Rancourt, died in 1966.

Survivors include a daughter, Alida R. Lewin of Fairfax.

The family suggests that expressions of sympathy be in the form of contributions to the Scholarship Fund, D.C. Chapter, American Guild of Organists, c/o Edward E. Schaefer, 3032 Gumwood Dr., Hyattsville, Md., 20783.