A Sentinel Health Event (SHE) is a preventable disease, disability, or untimely death whose occurrence serves as a warning signal that the quality of preventive and/or therapeutic medical care may need to be improved. A SHE (Occupational) is a disease, disability, or untimely death which is occupationally related and whose occurrence may: 1) provide the impetus for epidemiologic or industrial hygiene studies; or 2) serve as a warning signal that materials substitution, engineering control, personal protection, or medical care may be required. The present SHE(O) list encompasses 50 disease conditions that are linked to the workplace. Only those conditions are included for which objective documentation of an associated agent, industry, and occupation exists in the scientific literature. The list will serve as a framework for developing a national system for occupational health surveillance that may be applied at the state and local level, and as a guide for practicing physicians caring for patients with occupational illnesses. We expect to update the list periodically to accommodate new occupational disease events which meet the criteria for inclusion.