Bob passed away Thursday at his Los Angeles home after a series of brief illnesses, according to his longtime rep.

He's perhaps best known for his deadpan delivery, and his 2 successful sitcoms -- "The Bob Newhart Show" came first from 1972 to 1978, and costarred Suzanne Pleshette, Marcia Wallace and Peter Bonerz.

He returned to primetime again in 1982 with "Newhart," which ran until 1990. The series finale has been hailed as one of the greatest in TV history.

Bob wakes up in bed next to Pleshette -- who played his wife in his first sitcom -- and realizes the whole 8-year run of "Newhart" has been a dream sequence.

Newhart's comedy -- starting with his sketch and standup comedy recordings in the '60s -- earned numerous awards over the years ... including 3 Grammys 1 Emmy and a Golden Globe.

Before he broke into comedy, Bob was an accountant -- although, not a very good one ... which he frequently worked into his act. He also served in the U.S. Army when he was drafted during the Korean War.

Younger folks will recognize him for his role as Papa Elf in the Will Ferrell movie, "Elf" -- and he also had cameos in "Horrible Bosses" and a handful of "Big Bang Theory" episodes.

Bob is survived by his 4 children and 10 grandchildren. His wife of 60 years, Virginia Quinn, died last year.

He was 94.