Campylobacter jejuni was isolated from two ill persons from different families who were members of a closed community in rural Kansas. By October 29, seventeen additional members of the community had reported gastrointestinal illness. All persons reported consuming fresh cheese on October 20 that was made the same day at the Pioneer Day community fair from unpasteurized milk obtained from a local dairy. Of 101 persons who ate the cheese, 68 became ill. Although all samples of cheese tested negative for Campylobacter, results of the epidemiological investigation found an association between illness and consumption of fresh cheese made from unpasteurized milk during the fair. The unpasteurized cheese was made at an activity station by adding rennet extract to unpasteurized milk donated by a local dairy. Butter also was made, but from pasteurized milk. The cheese was served at a banquet that evening. One apparent case of secondary transmission occurred in a person who did not consume the fresh cheese, but became ill on October 29, 6 days after her child became ill.