Jackie Presser, the president of the International Brotherhood of Teamsters, the nation’s largest union, died at a hospital in the Cleveland suburb of Lakewood. He was 61.

Mr. Presser, who underwent brain cancer surgery in May, died at 10 p.m. on Saturday, said John Kerezy, a spokesman for Lakewood Hospital.

The cause of death, Kerezy said, was cardiac arrest. Mr. Presser had been admitted on June 28 with a blood clot on his right lung.

Mr. Presser had led the long-besieged Teamsters’ union back into the mainstream of American labor. Last fall, the union was readmitted to the American Federation of Labor and Congress of Industrial Organizations, which had ousted it in the 1950s over corruption charges.

That success notwithstanding, Mr. Presser had been able to do little to stem his union’s reputation for ties to the underworld.

On the day he was admitted to Lakewood hospital, the Justice Department filed suit in an effort to oust him and other senior leaders of the Teamsters and put the union under the control of a government trustee. The suit alleged a decades-long “devil’s pact” between the Teamster leadership and organized crime.

At his death, Mr. Presser was facing a federal trial on charges of siphoning union money with which to pay organized crime figures for jobs they had not performed. The trial had been delayed indefinitely because of his poor health.

His health also led Mr. Presser to announced in May that he was taking a four-month leave of absence. He turned over interim control of the union to its secretary-treasurer, Weldon L. Mathis.

Mr. Presser was the nation’s highest-paid union official, earning $530,000 from the Teamsters in 1984. But he seemed unconcerned that he took home more than many of the chief executive officers of the companies his members worked for.

“I’m a millionaire,” he said. “So what? I can’t be induced with bribes under the table. I can make a million through the union.”

An eighth-grade dropout and a former delivery boy, Mr. Presser became an influential and image-conscious union leader. When he took over the Teamsters’ top job in 1983, he promised to end their strong-arm reputation, which was as much a part of union lore as allegations that top Teamster officials had ties to organized crime.

It was an elusive goal. By the time he came to power, the union had been a subject of federal investigations for 30 years. Previous Teamster presidents had run into trouble dealing with both government and gangsters. Three of Mr. Presser’s four predecessors had been indicted, and he got his chance at the Teamsters’ presidency only because his immediate predecessor, Roy L. Williams, stepped aside after a bribery-conspiracy conviction in Chicago.

In his effort to lead the union on its uphill climb to respectability, he shed the pinky rings and diamond bracelets that he had worn as a union organizer in Cleveland and traded in his loud sports jackets for conservative, custom-tailored suits. He also tried diet after diet in a mostly unsuccessful effort to keep from tipping the scales at more than 300 pounds.

The grandson of a Jewish immigrant from Austria who fought on picket lines in the New York garment district, Mr. Presser was born in Cleveland on Aug. 6, 1926. His father was William Presser, a protege of the Teamster leader Jimmy Hoffa.