Joe DiMaggio Jr., 57, the troubled only child of the baseball Hall of Famer and a pallbearer at his father's funeral in March, died Aug. 6 at a hospital.

A hospital spokesman, who attributed the death to apparent natural causes, said Mr. DiMaggio was not breathing and had no heartbeat when he was brought by ambulance to Sutter Delta Medical Center late Friday. Attempts at resuscitation were unsuccessful, and he died about 11:25 p.m. Friday, the spokesman said.

Mr. DiMaggio, known as Joey D., was the only child of Joe DiMaggio and Dorothy Arnold, an actress whom the elder DiMaggio married in 1939 and divorced five years later. The elder DiMaggio did not have any children with his second wife, Marilyn Monroe.

Joe Jr., who struggled with substance abuse and homelessness during the last two decades, was estranged from his father and saw him infrequently in recent years. He was divorced and had two adopted daughters who were doted upon by their grandfather.

For many years, both father and son had refused to answer questions about their relationship.

Marie Amato Goodman, a cousin whose son was a close friend of the younger Mr. DiMaggio, said the son was unable to cope with his father's fame. She said, "He lived in the shadow of his father and could not rise above that."

Morris Engelberg, a close friend and attorney for the elder DiMaggio, said: "It's very sad. He loved his father. He turned down a seven-figure offer to do a book about Joe, as much as he could have used the money. He was broke."

Engelberg said Joe Jr. had suffered from asthma.

Mr. DiMaggio attended Yale University, but dropped out to enroll in the Marine Corps. In the mid-1970s, he had a blood clot removed from his head after a car accident. During the last two decades, he battled drug and alcohol problems. He often lived alone on the street and took shelter at one point in a trucking container. For a while, he was the manager of a trucking company in Oakland.

In 1995, he fractured his leg when the bicycle he was riding hit a van. He was cited by the California Highway Patrol for operating a bicycle under the influence of alcohol and had a permanent limp after the accident.

He lived in Pittsburg, Calif., in a trailer, and worked in a junkyard.

The younger Mr. DiMaggio and his wife, Susan, adopted daughters Paula and Katherine in the 1960s, but the marriage collapsed after six years.

The elder DiMaggio set up a trust fund that was to pay his son $20,000 a year. The bequest, in a will signed May 21, 1996, appeared to be the smallest gift in the document, which also established trust funds for DiMaggio's two grandchildren and four great-grandchildren.