A study examined the impact of the Centers for Disease Control's home study course in community hygiene on the job performance of 45 sanitarians in 30 districts throughout North Carolina. Data were collected from: (1) pre- and post-tests that evaluated the sanitarians' mastery of knowledge in such areas as water supply, sewage disposal, solid waste management, and disease prevention and control, and (2) "before/now" questionnaires for both participants and supervisors administered to assess behaviors and skills comprising job performance before and after the course. Analyses performed on the "before/now" statements revealed significance at the p < .0001 level. Besides gaining a large amount of technical knowledge in the area of environmental health, the sanitarians who successfully completed the course developed positive attitudes about the field of environmental health and became better prepared to meet the challenges of their jobs. (Both the sanitarian and supervisor questionnaires are included in the report.) (MN)