From 1979 to 1996, 58 patients (mean age, 39.4 years) were treated for bacteremia due to Campylobacter species at the Hospitals Vall d'Hebron in Barcelona, Spain. Bacteremia was considered to be hospital acquired in 30% of these patients. Almost all the patients (93%) had underlying conditions; liver cirrhosis was the most frequent (34% of patients), and neoplasia, immunosuppressive therapy, and human immunodeficiency virus disease were also common. Of the 58 Campylobacter strains isolated, 81% were C. jejuni, 10% were Campylobacter species, 7% were C. fetus, and one (2%) was C. coli. Resistance rates were: cephalothin, 82%; co-trimoxazole, 79%; quinolones, 54%; ampicillin, 20%; amoxicillin/clavulanate, 4%; erythromycin, 7%; gentamicin, 0; and tetracyclines, 0. Even though the majority of patients were immunocompromised, mortality was low (10.5%), and only one patient relapsed. Because of the high level of resistance to the quinolones in Campylobacter species, these drugs should not be used as empirical treatment, at least in Spain. Although the macrolides remain the antibiotics of choice, amoxicillin/clavulanate may be an effective alternative therapy.