He was secretary of state under President Bill Clinton from 1993 to 1997.
He reportedly died from complications of kidney and bladder cancer.
Christopher's family released a statement Friday night:
"Former Secretary of State Warren Christopher passed away peacefully, surrounded by family at his home in Los Angeles, on the evening of Friday, March 18, 2011. Mr. Christopher died from complications of kidney and bladder cancer. He was 85. Plans for a private memorial service are pending. A full obituary will be forthcoming shortly."