Robert Polhill, an American professor at Beirut University College who was held hostage in the Middle East for 39 months and who battled throat cancer upon his release from captivity in 1990, died July 1 at Georgetown University Hospital of complications from his cancer. He was 65 and lived in Arlington.

Mr. Polhill, a New York native, was working as an assistant professor of business studies when he and three fellow faculty members, Jesse Jonathan Turner, Alann Steen and Mithileshwar Singh, were seized Jan. 24, 1987, by gunmen posing as policemen on the college's campus.

The abductions represented the largest single kidnapping of Americans in Beirut and dramatized the hostage crisis in which numerous foreigners were held captive--and in some instances killed--by Lebanese militias in the 1980s.

Mr. Polhill endured isolation and a meager diet. A diabetic, he occasionally received doctor's visits and insulin shots. For the most part, he was chained in windowless rooms with little more than his imagination to break the monotony. He later said he fantasized about learning to play 37 instruments, writing songs and leading a band.

Maintaining a sense of humor was also a key to survival, he said during a 1992 reunion of hostages. He recalled a time when his captors wanted to take his picture, showing him in desperate shape so that it might prompt U.S. officials to act on the kidnappers' demands.

The guards emptied their Kalashnikov and Uzi weapons of the ammunition clips and pointed the guns at Mr. Polhill's temple. Everyone was laughing, and it took some time before everyone could put on a serious face.

"The first time he took the picture, I had a big grin on my face. I was laughing out loud, and the guy was really mad at me," Mr. Polhill said. "So he said, 'Look sad! Look sad!' I said I don't know how to look sad. . . . I was doing my best not to laugh . . . but I couldn't get the glint out of my eye."

As part of an effort to improve relations between Iran and the United States, he was released in April 1990.

Mr. Polhill was the first American to be released after the Iran-contra arms-for-hostages scandal broke in November 1986.

Appearing frail, hunched and gaunt, he was flown to an air base in Frankfurt, West Germany, where he was debriefed and placed under medical supervision. Tests showed that he had cancer of the larynx. He underwent surgery to remove a growth from his vocal cords, and his voice box was removed.

After weeks of radiation treatment and hospital recuperation, he returned to a hero's welcome in his native Beacon, N.Y., where residents held a parade and decorated the town with flags and yellow ribbons.

"He was always very positive, and even in his darkest moments, he never lost his sense of humor," said his wife, Ferial Polhill. Despite his ordeal, he remained close to Lebanon and its people, Polhill said. "He always distinguished between those who held him captive and the Lebanese people in general."

It was a love of the country that led him in 1983 to move there and take a teaching position at Beirut University College. He had earlier traveled to Lebanon on business trips while working as an accountant for a New York City firm.

He attended Cornell University and graduated from New York University in 1961.

In recent years, he had traveled the country, lecturing on surviving cancer and diabetes. In addition to his wife, of Arlington, survivors include two sons, Stephen Polhill and Brian Polhill, both of New York City; and his mother, Ruth Polhill of Rochester, N.Y.