Robert Chartoff, the Oscar-winning producer behind classic boxing movies Rocky and Raging Bull, has died at the age of 81.

Chartoff died at his home in Santa Monica, California, according to Lynn Hendee, the president of his company Chartoff Productions. He had been suffering from pancreatic cancer.

He had been a movie producer for nearly a decade when he found his career-defining hit in 1976's Rocky, the small-budget Sylvester Stallone movie that became a blockbuster and won three Academy Awards including best picture.

Chartoff went on to produce all seven movies in the Rocky series, including the forthcoming Creed, which is in post-production and due for release later this year.

He also produced a different, darker take on boxing in the Martin Scorcese-directed Raging Bull in 1980.

Born in Depression-era New York City, Chartoff teamed up with partner Irwin Winkler to produce the Rocky series.

He kept working into his late 70s and 80s, and his recent credits including 2013's Ender's Game with Harrison Ford and last year's The Gambler with Mark Wahlberg.

His other credits included 1983's The Right Stuff, which won four Oscars, and 1969's They Shoot Horses, Don't They? a cult hit starring Jane Fonda.

He had five children with three different wives, and is survived by his current wife Jenny Weyman.