Campylobacter continues to be one of the most common bacterial causes of diarrheal illness in the United States and worldwide. Infection with Campylobacter causes a spectrum of diseases including acute enteritis, extraintestinal infections, and postinfectious complications. The most common species of Campylobacter associated with human illness is Campylobacter jejuni, but other Campylobacter species can also cause human infections. This comprehensive review includes discussion of the taxonomy, clinical manifestations of infection, epidemiology and the different methods of laboratory detection of Campylobacter.