Manzarek died in Rosenheim, Germany, surrounded by his family, Manzarek's publicist said. According to manager Tom Vitorino, Manzarek had bile duct cancer.
Manzarek and Jim Morrison first met Jim Morrison at UCLA film school. They ran into each other in Venice a few months after graduation. The Doors' original lineup, which also included drummer John Densmore and guitarist Robbie Krieger, was only together for a few years.
The group is best known for hits like "L.A.Woman," ''Break On Through to the Other Side," ''The End" and "Light My Fire." The Doors went on to become one of the most successful rock 'n' roll acts to emerge from the 1960s, selling more than 100 million records and songs.
The Chicago native remained active in music even after Morrison's death in 1971. He briefly tried to keep the band going, but the group would eventually disband.
Manzarek played in other bands over the years, produced other acts, became an author and worked on films.
Manzarek leaves behind his wife, Dorothy, his son Pablo and two brothers, Rick and James. Funeral arrangements are pending.
The Associated Press contributed to this report.