Subjects for the study were drawn from a larger sample of inmates whose prison careers were being followed under a project funded by the National Institute of Mental Health. The original cohort consisted of 10,534 male inmates released from New York State prisons between July 30, 1983, and September 1, 1984. A stratified random sample of 2,496 inmates was selected for further study. Inmates diagnosed with antisocial personality did not differ from other diagnosed inmates in terms of background characteristics, except race. About two-thirds of black diagnosed inmates received the diagnosis of antisocial personality; only about one-third of whites received this diagnosis. Inmates diagnosed with antisocial personality also differed in terms of criminal histories. Inmates diagnosed with antisocial personality were more likely to have at least one prior violent crime on their records than other diagnosed inmates. They were also more likely to have a prior imprisonment. Directions for future research relative to inmate diagnosis are offered. 29 references and 6 tables