Richard Feynman was 69 years old when he died.
He was born on May 11, 1918, in New York City, and died on February 15, 1988, in Los Angeles. Because his death occurred several months before his 70th birthday, the correct age was 69—not 70. This is also why contemporary obituaries commonly described him as having died “at 69.”
Feynman had battled serious illness for about a decade. In 1978, doctors diagnosed liposarcoma, a rare cancer, and surgery removed a large tumor that had damaged his kidney and spleen. Later, he developed Waldenström macroglobulinemia, another rare cancer. Further operations followed in 1986 and 1987.
Near the end of his life, a ruptured duodenal ulcer caused kidney failure. Feynman declined dialysis that might have prolonged his life for only a few months and died on February 15, 1988. His death came less than three months before the 70th anniversary of his birth.