Campylobacter jejuni (and also Campylobacter coli) are currently thought to be the number one cause of sporadic bacterial gastrointestinal infection in the United States. Complications do occur, although infrequently, and recent studies suggest a strong association of Campylobacter infection with Guillain-Barré syndrome. There are no specific clinical findings that differentiate Campylobacter species from other causes of infection, and diagnosis is dependent on laboratory testing. There are still many clinical laboratories that do not routinely look for C. jejuni in routine stool cultures as should be standard practice. New species of Campylobacter associated with gastrointestinal infections have been recently identified that may not be recovered by methods used for the more common C. jejuni. Clinical studies on antimicrobial therapy of Campylobacter infections show variable effects on symptoms but ensure microbiologic cure. New studies suggest that development of quinolone resistance during therapy is common with Campylobacter species, which may limit quinolone therapy in the future.