Eight patients with Campylobacter fetus bacteremia, six of them with serious underlying diseases, were seen in a two-year period. Besides fever, which was observed in all cases, the most frequent clinical manifestation was lower extremity phlebitis and cellulitis (four patients). In one of these patients, it had the peculiar aspect of bilateral pretibial cellulitis. One patient had vertebral osteomyelitis, a complication, to our knowledge, not yet described. Two patients, both with advanced underlying diseases, died. The five patients who completed a two- to three-week course of erythromycin gluceptate, all had initial clinical improvement. However, one patient suffered a relapse at the end of treatment, and progression of vertebral osteomyelitis while on erythromycin therapy was observed in another patient. These clinical and bacteriologic failures occurred despite the in vitro sensitivity to erythromycin of the two strains. This suggests that erythromycin might not be adequate therapy for C fetus septicemia.