This study assessed the risk of cancer mortality and incidence among 2559 employees exposed to acrylonitrile in the production of Orlon at 2 plants in 1944-1991. Latency, duration of exposure, highest level of exposure ever experienced, and cumulative exposure were used as indicators of exposure. The average duration of exposure for the workers was 7.6 years with an average cumulative exposure of 57.6 ppm-years. Overall mortality was lower than expected in a comparison with the United States population and all DuPont employees [454 deaths, standardized mortality ratios (SMR) of 69 and 91, respectively)]. All the cancer death ratios were lower than expected in a similar comparison. The SMR values for specific sites did not differ significantly from the expected values. Mortality from all cancers and from prostate, respiratory, and digestive cancer did not show any significantly associated increases or a consistent pattern suggestive of a dose-response. The cancer morbidity patterns were similarly unremarkable.