Dr. Howard Bancroft Andervont, a cancer researcher who directed many early and valuable studies linking cancer to viruses, died of a stroke Wednesday at a hospital in Sarasota, Fla. He was 83.

A longtime resident of Bethesda, he was on vacation when he was stricken.

Dr. Andervont was the first chief of the biology laboratory of the National Cancer Institute and held that post from the 1940s until 1961, when he became editor of the institute's Journal. He retired in 1968.

A virologist and an authority on filterable viruses and cancer, he studied viruses as cancer-causing agents decades before others began research in this field.

He began his career in 1927 at the Harvard School of Public Health and Medicine, where he was an instructor in epidemiology and preventive medicine. He and his colleagues there convinced the U.S. Public Health Service that cancer was a public health problem. Subsequently, they and Public Health Service colleagues formed the original staff of the National Cancer Institute when it was established in the late 1930s.

Dr. Andervont's research on the immunology of transplanted tumors in genetically-controlled mice developed methods of cancer research that are still valid. His experiments on the transmission of the herpes virus in mice by intracerebral inoculation provided a method for studying this human virus in an experimental animal. Other research successfully produced viral tumors in fowl for the first time.

This work, and experiments demonstrating the transmission of tumor agents by male and female mice to their infants, established that some types of cancer in mammals are caused by viruses. Continued research in this area is still seeking to establish such a link between viruses and cancers in humans.

As chief of the National Cancer Institute's biology laboratory, Dr. Andervont remained in the forefront of cancer research, directing a broad program of specialties that ranged from tissue culture and electron microscopy to genetics and cell biology, which produced cancer by chemical and viral agents.

A native of Canton, Ohio, he graduated from Mount Union College in Ohio. He earned a doctorate from Johns Hopkins University and spent a year there as a Carnegie Foundation Fellow.

Dr. Andervont was a member of many scientific societies and numerous committees of the American Cancer Society and was a former president of the American Society of Cancer Research.He was the author of 165 scientific reports in his field.

He was awarded an Distinguished Service Award from the Department of Health, Education and Welfare in 1961 and received the National Civil Service League Award the following year.

Survivors include his wife of 55 years, Letha, of Bethesda; two daughters, Barbara Bowman of Syosset, N.Y., and Carolyn B. Edie, of Chicago; a son, John D., of Gaithersburg, and two grandchildren.