Findings from the National Criminal Justice Drug Abuse Treatment Studies (CJ-DATS) National Criminal Justice Treatment Practices survey are examined to describe types of services provided by three types of prisons: those that serve a cross-section of offenders, those that specialize in serving offenders with special psychosocial and medical needs, and those that specialize in serving legal status or gender specific populations. Information is presented on the prevalence and type of specialized prisons and services provided to offenders as reported by wardens and other facility directors drawn from a nationally representative sample of prisons. Additional analyses explore organizational factors that differentiate prisons that serve specialized populations including staffing, training, other resources, leadership, and climate for change and innovation. Implications for expanding and improving services for special populations in correctional settings and the values of specialized prisons are discussed. © 2007, Sage Publications. All rights reserved.