We report a case of aneurysm of the abdominal aorta with spontaneous rupture in a 64-year-old man with emphysema and chronic alcoholism. Campylobacter fetus subspecies fetus was repeatedly recovered from the blood and from specimens of the excised aneurysm. The patient died in spite of early diagnosis, intravenous erythromycin and surgical intervention. The bacteriology and epidemiology of campylobacteriosis in man is briefly discussed and eight other published cases of aneurysm, infected with the same organism, are tabulated. C. fetus ssp. fetus should be added to the list of bacteria having a tropism for vascular endothelium.