Food borne illnesses continue to cause substantial morbidity and mortality in the United States, primarily as gastroenteritis but occasionally as other syndromes as well. Most of these illnesses are caused by a variety of widely known infectious agents, principally viruses, and are probably the result of common mistakes in food handling in the home or in restaurants. The epidemiology of food borne illness is evolving. Major changes in food production, distribution, and consumption have created opportunities for new pathogens to emerge and for old ones to reemerge, and the potential for widespread outbreaks is increasing. Antibiotic resistance in bacterial pathogens resulting from the widespread use of antimicrobial agents in animal husbandry is also an important concern. Clinicians must be aware of the changing epidemiology of food borne illness to recognize and manage these conditions in the clinical setting. In addition, clinicians are critical in the reporting of recognized or suspected food borne illness, so that public health authorities are able to investigate, understand, and ultimately better control them. A number of new techniques have been employed, and others under development will improve our ability to recognize and cope with food borne diseases.