Dr. Milo David Leavitt Jr., 68, a retired official of the National Institutes of Health who served as science policy coordinator and deputy assistant secretary for science and population at the old Department of Health, Education and Welfare in 1966 and 1967, died of cancer on Jan. 12 at his home in Silver Spring.

From 1978 until shortly before his death, Dr. Leavitt was a special assistant to the director of the National Institute on Aging and deputy associate director of NIH's Biomedical Research and Clinical Medicine program.

Dr. Leavitt was born in Beloit, Wis. He graduated from the University of Wisconsin and took his medical degree at the University of Pennsylvania. He was a captain in the Army Medical Corps in World War II. From 1949 to 1958, he taught at the Woman's Medical College in Philadelphia.

In 1959, he took a master's degree in public health at Harvard University.

Dr. Leavitt begn his career at NIH in 1961. One of his principal interests was the improvement of training for treatment of the elderly. After his stint at HEW, he returned to NIH as director of the John E. Fogarty International Center for Advanced Study in the Health Sciences. He held that post until 1978.

He leaves no immediate survivors.