Nope, no relation. Kate did have an actress niece, Katharine Houghton, and they appeared in Guess Who's Coming To Dinner together.
Katharine Hepburn (1907-2003) was a 12-time Oscar-nominated, and four-time Oscar winner as well as a bestselling author. Her two Memoirs, "Me" and "The Making of the African Queen" were huge sucesses.
No
Katharine Hepburn died of natural causes. She died on June 29th, 2003.
On June 29, 2003, Hepburn died of natural causes at Fenwick, the Hepburn family home in Old Saybrook, Connecticut.
Katharine Hepburn died on June 29, 2003 at the age of 96.