Beulah N. Mathis, 61, chief of the statistical methods section, mathematical statistics branch of the Internal Revenue Service, died of cancer Monday at George Washington University Hospital.

Mrs. Mathis was born in The Bronx, N.Y., and grew up in Queens. She graduated from Hunter College for Women in New York City.

She first came to Washington during World War II and worked for the Office of Defense Transport, the War Relocation Authority and the U.S. Public Health Service. In 1949, she and her husband, Meyer Mathis, moved to this area from New York to live permentaly when he took a position with Red Cross national headquarters here.

Mrs. Mathis began her career with the IRS in 1965 as a statistican.

She was a member of the American Statistical Association and the American Association for the Advancement of Science.

She also was a past-president of the Sisterhood of Congregation Har Tzeon in Wheaton.

In addition to her husband, of the home in Rockville, survivors include three sons, Mark, of Bethesda, Jeremy, of London, England, and Maurice, of New York City; Her mother, Anna Nechemias, of Atlantic City, N.J.; two sisters, Pearl Chalofsky of Willingboro, N.J, and one grandchild.

The family suggests that expressions of sympathy be in the form of contributions to Congregation Har Tzeon in Wheaton. CAPTION: Picture, BEULAH N. MATHIS