We describe the isolation and identification of a Helicobacter (Campylobacter)-like organism obtained from the blood of a 32-year-old homosexual man with a 10 months' history of AIDS and progressive mucocutaneous Kaposi sarcoma. Fever and bacteremia persisted despite sequential administration of ciprofloxacin and trimethoprim-sulfamethoxazole, antibiotics reported to be active against this organism in vitro. Facultative organisms like Campylobacter fennelliae and Campylobacter cinaedi which are difficult to isolate by standard techniques may be important but unrecognized causes of febrile illness in patients with human immunodeficiency virus infection. Laboratories should consider use of acridine orange staining and more extensive subculture protocols for blood cultures with progressive growth indices which appear negative by conventional staining and subculture technique.