To help primary care residency programs develop or improve residency curricula in occupational and environmental medicine, the National Institute for Occupational Safety and Health launched a train-the-trainer initiative. This project was called EPOCH-Envi (Educating Physicians in OCcupational Health and the Environment). From 1990 to 1996, 46 2-day curriculum development workshops were held. These featured (1) guidelines on how to plan, implement, and evaluate a curriculum, (2) continuing education on occupational illnesses and injuries, (3) a worksite or environmental site visit, and (4) information resources. A total of 435 faculty from 305 residency programs participated, representing 42.5% of the family practice residencies and 24.9% of the internal medicine residencies in the United States. A survey conducted among attendees (60.4% response rate) 17 months after their workshop revealed that 65.6% of respondents had added lectures on occupational and environmental topics to the residency curriculum. Other curriculum improvements were also made. Primary care physicians manage most patients with occupational and environmental health problems or concerns. Providing technical assistance specifically designed to support occupational and environmental health education in primary care residencies can have a positive impact on curriculum content.