Albert B. Sabin, 86, who developed the oral vaccine for poliomyelitis, died of congestive heart failure yesterday at Georgetown University Medical Center.

It was estimated that by the time of his death about 5 million cases of polio and 500,000 deaths had been prevented by his vaccine worldwide.

President Clinton called Sabin "one of the great heroes of American medicine."

Sabin, an immigrant who was born in the eastern Polish city of Bialystok in 1906, became a towering figure in the world of medical research, and he worked on many other diseases besides polio.

During World War II, he turned his attention to illnesses that were plaguing U.S. troops in Africa and the South Pacific. He isolated viruses for sand fly fever, found a vaccine for dengue fever and developed a vaccine against Japanese encephalitis.

His great ambition was to see polio eradicated throughout the world in his lifetime. According to Robert Kim-Farley, director of the Expanded Programme on Immunization of the World Health Organization, eradication is a goal that is within reach on a world scale and one that virtually has been accomplished in the United States.

In 1952, there were about 21,000 polio cases in the United States. Ten years later, there were fewer than 1,000. And in the last 18 months, Kim-Farley said yesterday from WHO headquarters in Geneva, "there hasn't been a single case of polio anywhere in the Western Hemisphere."

That "is the start of Sabin's legacy," he said, saying WHO expects to "literally wipe polio off the face of the Earth" by 2000.

By the mid-1950s, Sabin was ready to test his oral vaccine, which was made from live viruses and administered on a lump of sugar. In the meanwhile, Jonas Salk had produced an injectible virus. The two scientists began a rivalry that was to continue throughout their lives, often steeped in bitterness and open hostility.

Yesterday, Salk described his rival's death as "a great loss. . . . His contributions toward the control of polio will endure long in the future."

When Sabin came to this country, he spoke no English. He soon learned enough to finish high school in New York City. He then went on to New York University, from which he received bachelor's and medical degrees. The doctor used to say that an uncle had agreed to pay for his education as long as he studied dentistry. Sabin began on that course, but gave it up even though his relative withdrew his financial support.

Drawn irresistibly to medical research, he began his work on polio almost as soon as he finished his studies at NYU. Polio was one of the most feared diseases of its day, and its most famous victim was President Franklin D. Roosevelt, who was stricken with it in the 1920s and paralyzed from the waist down.

From 1935 to 1939, Sabin was at the Rockefeller Institute for Medical Research in New York. Then he moved to the University of Cincinnati College of Medicine and the Children's Hospital Research Foundation, where he stayed for 30 years. From 1970 to 1972, he was head of the Weizmann Institute of Science in Rehovat, Israel.

The Sabin vaccine was deemed by most members of the scientific community to be safer and more effective than the Salk vaccine. It also was easier to administer. But both vaccines served almost immediately to put an end to epidemics of the childhood paralyzing disease and eventually to turn row upon row of artificial breathing machines, the so-called iron lungs, into so much junk.

Kim-Farley said Sabin's contribution lay not only in the vaccine he developed, but also in the discovery that the most effective method of protection against the disease is mass immunizations. The "tame" live virus he used not only immunized the individual by stimulating the body to make antibodies, but it actually displaced the so-called wild virus, making it impossible for the disease-causing organism to infect others.

Mass applications of the Sabin vaccine began in the early 1960s with "Sabin oral Sundays," in which people would eat sugar cubes that had the vaccine.

About a decade ago, while working on an aerosol measles vaccine, Sabin was stricken with a paralyzing illness, later identified as Guillain-Barre syndrome. He was treated at Johns Hopkins Hospital and at the National Institutes of Health, where he also served as an adviser in the neurology institute and to the team battling AIDS.

Sabin was a Washington resident in recent years. His first wife, the former Sylvia Tregillus, whom he married in 1935, died in 1966. His marriage to Jane Warner ended in divorce.

Survivors include his wife, the former Heloisa Dunshee de Abranches, whom he married in 1972, of Washington; two daughters from his first marriage, Amy Horne of Palo Alto, Calif., and Deborah Sabin of Yakima, Wash.; and three grandchildren.