John B. Sterling, 70, who had been active in Montgomery County real estate circles for the past 50 years, died of cancer Saturday at his home in Silver Spring.

He had been an accountant and office manager for Col. E. Brooke Lee for more than 50 years and a co-owner of Sterling & Scull, a Silver Spring property management firm, for more than 35 years. He also was a real estate broker.

Mr. Sterling was a member of St. Michaels Catholic Church in Silver Spring and belonged to the Rosensteel Council of the Knights of Columbus. He also was a member of the Moose Lodge in Silver Spring.

Mr. Sterling was a native of Leonardtown, Md., where he had been a charter member of the Leonardtown Fire Department. He had lived in Silver Spring since 1929.

He was a graduate of the old Leonard Hall School and attended Benjamin Franklin University at night.

Survivors include his wife, Nell, a son, John M. (Jack), and a daughter, Joyce Ann Sterling all of Silver Spring; three sisters, Lucille Cheseldine of Mt. Airy, Md., and Mary Catherine Bell and Mary Theresa Sterling, both of Leonardtown; six brothers, James H., of Hawaii, Hugh D., of White Plains, Md., and B. Harris. William O.E., Walter K., and Lynwood J. Jr., all of Leonardtown.

The family suggests that expressions of sympathy be in the form of contributions to the Little Sisters of the Poor in Baltimore.