On February 6, 1976, while waiting in a motel room between sets at Menlo Park's Butterfield's nightclub, Guaraldi died of a sudden heart-attack. He was only 47 years old.
A few weeks later, on March 16, "It's Arbor Day, Charlie Brown" debuted on television. It was the 15th, and last, Peanuts television special to boast Guaraldi's original music. He had just finished recording his portion of the soundtrack on the very afternoon of the day he died.