Cardiobacterium hominis, a recently recognized Gram-negative pathogen, was recovered in blood cultures from a 65-year-old man with indolent endocarditis of previously normal heart valves. Despite the low virulence of the organism, major cardiac damage required valvular replacement, and there were multiple cerebral emboli with development of a mycotic aneurysm. After bacteriological cure, he died of a ruptured aneurysm.