Campylobacter jejuni is the most common enteric pathogen isolated from university and college students in the United States. During the fall and winter quarters of the 1983-1984 academic year, the authors conducted a case-control study at the University of Georgia, Athens, Georgia, to identify risk factors for C. jejuni enteritis. Students with diarrhea whose cultures yielded C. jejuni were compared with controls matched by age, sex, and residence. A total of 45 case-control pairs were interviewed about exposures during the week before the case's onset of illness. The infections occurred sporadically and were caused by a wide variety of C. jejuni serotypes. Three risk factors were identified: eating fully cooked chicken, eating chicken reported to be raw or undercooked, and contact with a cat or kitten. No case reported drinking raw milk. No significant association was found between illness and the places where chicken meals were prepared or the specific manner in which chicken was cooked. Chicken may be the principal vehicle of transmission for sporadic Campylobacter enteritis among college students.