The in vitro antimicrobial activities of different antimicrobial agents on Campylobacter jejuni from human and animal origins were compared by using a Dynatech MIC 2000 system. In general, the minimal inhibitory concentration distributions for the human strains were very comparable with those of the animal strains. The animal strains had a bimodal distribution for ampicillin, clindamycin, and tetracycline.