Five cases of Campylobacter fetus bacteremia are reported. This germ, found in blood cultures, induces high fever and is accompanied by either gastroenteritis with colitis or thrombophlebitis. Other, but much rarer septic sites are the meninges and endocardium. Patients already debilitated by chronic disease are more susceptible to bacteremia with Campylobacter fetus, which worsens the prognosis of the infection. Although non-debilitated patients can contract this infection, the prognosis here is more favourable. Antibiotic treatment is indicated in all cases. Campylobacter fetus bacteremias are rare and their pathogenesis still little understood. This "microaerophil" germ does not survive in air which makes culturing difficult under ordinary conditions. On the other hand, Campylobacter jejuni induces gastrocolitis with spontaneous recovery. It is found in feces and thrives in contaminated water and milk.