Urbanus E. Baughman Jr, 73, chief of the U.S. Secret Service under three presidents, died of arteriosclerotic heart disease yesterday at the Community Memorial Hospital in Tom's River, N.J.

Mr. Baughman spent 34 years in the Secret Service. He began as a clerk-stenographer in the philadelphia office in 1927. He got several assignments as an undercover officer in cases involving counterfeit money and was promoted to agent in 1934. He later held supervisory posts in Washington, Newark, N.J., Philadelphia and New York City. He became chief of the service in 1948 and held the post until his retirement in 1961.

During his tenure as chief, Puerto Rican nationalists made an attempt on the life of President Truman at Blair House, where the Trumans were living during renovation of the White House.

The attempt ended with one White House policeman and one would-be assassin shot dead. Although Truman was in Blair House at the time and stuck his head out the window to see what was going on, he was uninjured.

While chief of the service, Mr. Baughman also supervised the successful investigation of the theft of $160,000 from the U.S. Bureau of Engraving and Printing, reorganized the service to provide more administrative control from Washington, and saw to the personal safety of President Eisenhower and Kennedy as well as that of President Truman.

He kept an epigram in his office at the Treasury Department which read, "You ain't learnin' nothin' when you're talkin'."

Associates said Mr. Baughman also prided himself on the fact that he had never been shot at during his Secret Service career. They said he regarded this as a measure of his skill as an investigator.

His investigations were numerous and they involved some colorful characters. Mr. Baughman began getting his experience as a crime-fighter while still a clerk-stenographer, it being the custom in those days for potential agents to enter the service in that grade.

In 1932, when the governor of the Federal Reserve Bank in Philadelphia received extortion letters, Mr. Baughman was detailed to act as an undercover man and deliver $5,000 to the gang. They had threatened to kill the governor of New Jersey if they were not paid.The result was the arrest of two extortionists.

In 1934, he succeeded in buying counterfeit money from Alfonso Filipone, who had just finished serving an eight-year prison term.Filipone was arrested and the money was traced to a counterfeiting ring in New York.

Other cases in which Mr. Baughman took part involved a woman who ran a restaurant in a fashionable part of Philadelphia who later turned out to be involved in a murder; a preacher in Camden, N.J., who later was convicted of arranging his own daughter's death, and the arrest of Herman Petrillo, a member of the so-called Philadelphia arsenic murder ring. Members of the ring were prosecuted for 21 known murders.

In 1941, Mr. Baughman was transferred from Philadelphia to New York City as assistant supervising agent. Two years later he was named supervising agent in Newark. From 1943 to 1948, he served in New York and Washington. He became chief of the service in November 1948.

In 1961, the year he retired, Mr. Boughman published a book written with Leonard Wallace Robinson entitled "Secret Service Chief." In 1965, he moved from Arlington to Pine Beach, N.J.

Survivors include his wife, the former Ruth Yessel, of the home in Pine Beach; a son, William E., of Atlanta, and two sisters, Mrs. Walter Pine, of Annandale, and Mrs. Edna Denny, of Leesburg, Va.