Melendez died of natural causes Tuesday at St. John's Health Center, according to publicist Amy Goldsmith.
Melendez's nearly seven decades as a professional animator began in 1938 when he was hired by Walt Disney Studios and worked on Mickey Mouse cartoons and classic animated features such as "Pinocchio" and "Fantasia."
He went on to animate TV specials such as "A Charlie Brown Christmas" and was the voice of Snoopy, who never spoke intelligible words but issued expressive howls, sighs and sobs.
Melendez was born in 1916 in Hermosillo in the Mexican state of Sonora. He moved with his family to Arizona in 1928 and then to Los Angeles in the 1930s, attending the Chouinard Art Institute.
Melendez took part in a strike that led to the unionization of Disney artists in 1941, and later moved to Warner Bros., where he worked on Bugs Bunny, Porky Pig and Daffy Duck shorts.
In 1948, Melendez left Warner Bros. and over the next 15 years worked as a director and producer on more than 1,000 commercials and movies for United Productions of America, Playhouse Pictures and John Sutherland Productions.
At UPA, he helped animate "Gerald McBoing-Boing," which won the 1951 Academy Award for best cartoon short.
Melendez met "Peanuts" creator Charles M. Schulz in 1959 while creating Ford Motor Co. TV commercials featuring Peanuts characters.
The two became friends and Melendez became the only person Schulz authorized to animate his characters.
Melendez founded his own production company in 1964 and with his partner Lee Mendelson went on to produce, direct or animate some 70 "Peanuts" TV specials, four movies and hundreds of commercials.
The first special was 1965's "A Charlie Brown Christmas." The show reportedly worried CBS because it broke so much new ground for a cartoon: It lacked a laugh track, used real children as voice actors, had a jazz score and included a scene in which Linus recited lines from the New Testament.
However, the show was a ratings success and has gone on to become a Christmastime perennial.
Melendez created Emmy-winning specials based on the cartoon characters Cathy and Garfield, and was involved in animated versions of the Babar the elephant books and the C.S. Lewis book, "The Lion, the Witch and the Wardrobe."
He also was co-nominee for an Academy Award in 1971 for the music for "A Boy Named Charlie Brown."
In all, his productions earned some 19 Emmy nominations, including six awards.
Melendez is survived by his wife Helen; sons Steven Melendez and (Ret.) Navy Rear Adm. Rodrigo Melendez, six grandchildren and 11 great-grandchildren.