To obtain a comprehensive picture of the levels of mental disability in the general state prison population in New York State, the authors gathered data on a random sample of inmates using a survey instrument adapted from the state's level-of-care surveys of the psychiatric population. The sample consisted of 3,332 inmates in the general prison population (9.4 percent) and 352 inmates in prison mental health units. The survey results showed that 8 percent of the state's prison inmates have severe psychiatric or functional disabilities that clearly warrant some type of mental health intervention, and another 16 percent have significant mental disabilities that require periodic services. The specific nature and extent of these disabilities need to be assessed before appropriate services can be developed.