A 36-year-old homosexual man who was infected with human immunodeficiency virus presented with a 2-month history of fever and intermittent diarrhea. Stool cultures were negative for bacterial pathogens, ova, parasites, and acid-fast organisms. An initial blood culture became positive after 5 days for a curved, gram-negative rod that was identified later as Campylobacter cinaedi. The patient received a series of antibiotic regimens, including a 2-week course of erythromycin followed by a 2-week course of tetracycline, but follow-up blood cultures continued to yield C. cinaedi. The patient was then treated with a 2-week course of oral ciprofloxacin; he remained asymptomatic 11 weeks later, at which time a blood culture was negative for C. cinaedi. To the best of our knowledge, this is the first documented case of symptomatic bacteremia due to C. cinaedi that was successfully treated with ciprofloxacin.