John B. (J.B.) Sterling III, 17, a junior at Northwood High School in Silver Spring, died of leukemia Tuesday at his home in Silver Spring.

The leukemia was diagnosed in November 1975, but the youth continued to attend classes until recently. He was born in Washington and grew up in Silver Spring.

He had been active as a volunteer with the Silver Spring YMCA, logging more than 800 hours in the last five years.

He was a junior camp counselor working with youngsters six to 15 years old in the YMCA's Afterschool Day Care Program and the Values Clarification Program. He was a member of the Sunshine Outreach Center Youth Corps and the Junior Leader's "Y" Club.

He also participated with his father, John M. Sterling, in a number of bowling leagues and was honored with a "Special Merit" award from the Sunday Adult-Youth Leagues at the Wheaton Fair Lanes.

In addition to his father, he is survived by his mother, Addie T. Sterling, both of the home; a sister, Lyn, of Silver Spring, and his grandparents, John B. and Nell Sterling, also of Silver Spring.

The family suggests that expressions of sympathy be in the form of contributions to the Research Foundation at Children's Hospital. CAPTION: Picture, JOHN B. (J.B.) STERLING III