Major work related diseases and injuries and strategies for preventing them were discussed. The ten leading work related diseases and injuries according to a list compiled by NIOSH in 1983 are occupational lung diseases, musculoskeletal disorders, occupational cancer, severe traumatic injuries, occupational cardiovascular diseases, reproductive disorders, neurotoxic disorders, noise induced hearing loss, skin disorders, and psychological disorders. By preparing the list, NIOSH intended to encourage discussion among professionals about the major problems in occupational health, to assist in setting national priorities for preventing work related health problems, and to convey to a diverse audience the concerns and activities of NIOSH. The changing nature of health care was discussed. Health care historically focused on curing disease and repairing injuries. It was noted that because of the long latency periods associated with such diseases as cancer and lung disorders a large pool of chronically ill people has accumulated as a result of occupational exposures. The emphasis in occupational health has been changed to prevention. Strategies for preventing occupational diseases and injuries were discussed. NIOSH presented national strategies for each major disease or injury listed at symposia in 1985 and 1986. These strategies emphasized surveillance, research, training, and applying and adapting existing knowledge. The author concludes that most of the illnesses and injuries that occur today result from a failure to use existing knowledge. By working together, sharing knowledge, and cooperating, occupational illnesses and injuries can be prevented.