Since 1988, the National Institute for Occupational Safety and Health (NIOSH) has notified workers who were subjects in occupational epidemiology studies of the study findings ("worker notification"). This paper describes seven notifications and the worker's reactions to them. The chemicals of interest in the studies were: carbon monoxide, o-toluidine, bis-chloromethyl ether, polychlorinated biphenyls, cadmium, acid mist, and dioxin. Materials describing the study results were sent to 15,958 subjects who were notified of their increased risk of arteriosclerotic heart disease, bladder cancer, lung cancer, melanoma, kidney dysfunction, laryngeal cancer, all cancers combined, or soft tissue sarcoma. Workers provided feedback via telephone calls, and for three notifications, by postcards containing workers' comments and ratings of the notification materials. The percentage of telephone calls received from notified workers ranged from 0.3% to 3.8%, and the percentage returning postcards ranged from 8.8% to 17.6%. The two largest categories of callers were those with questions about their disease risk (30%) or who reported on their health status (25%). Most of the comments on postcards (26%) were complimentary or expressed appreciation for receiving the letters; reports of ill health were second (20%). A majority (66%) rated the notification materials well done. Few of the callers (5%) requested information on legal issues. Most (85%) did not find the materials, which ranged in reading level from sixth to ninth grade, too hard to read, although 15% reported difficulty reading them. Although this response system was effective in producing some input from workers, its limitation is that respondents may not be representative of all notified workers. However, such information is useful because there are few data on the effects of notifications on workers.