Paul Hill, 65, who as founder and leader of the 180-voice singing group that bore his name was a major figure in Washington's musical life since the 1960s, died last night at his home in Potomac. He had amyotrophic lateral sclerosis, also known as Lou Gehrig's disease.

The degenerative ailment prompted his retirement in 1996 from the Paul Hill Chorale, which had been a Washington institution since he founded it in 1967. Appearances by the group included almost 200 concerts at the John F. Kennedy Center for the Performing Arts.

On April 17, 1996, Mr. Hill announced that he would step down as the conductor and artistic director of the much-lauded symphonic chorus, made up of professional and recreational singers.

"We've come a long way in the last 29 years," Mr. Hill said at the time. When the group made its debut at Constitution Hall, he said, "we weren't really a very good choir."

But, he said, "we became a very good choir . . . because we kept at it--work, work, continual work, continual growth."

Donald J. McCullough was named to succeed him, but Mr. Hill said he would try to remain active. "I'm going to keep getting in the way just as much as I can," he said.

A family member said last night that Mr. Hill had been sustained by a ventilator for some time, but managed to keep working. Until about a year ago, she said, he had served in an advisory role to the singing group.

In the late stages of his illness, she said, he communicated through a computer that translated eye movements into letters and words.

Under Mr. Hill, the chorale developed what was described in news accounts as Washington's first sing-along performance of the "Messiah," which became a Christmas tradition here. He was also credited with founding Washington's first professional chamber chorus, the Washington Singers. He conducted in 27 states and five European countries. The chorale has been seen on television and heard on radio.

A brass player at the outset of his musical career, Mr. Hill won a prize for trombone playing and marched in the Tournament of Roses Parade in Pasadena, Calif., playing a sousaphone. He had been in the Roger Wagner Chorale and a high school band director in California.

While in that post, he was asked to fill in for a choir director who left in the middle of the semester. He knew then, he said, that leading singing groups "was going to be my life's work. . . . I have loved every minute of it."

CAPTION: Although Paul Hill had Lou Gehrig's disease, he served in an advisory role to the Paul Hill Chorale until a year ago.