Most research into psychopathy among prisoners is based on selected samples. It remains unclear whether prevalences are lower among European populations. This study aimed to measure the prevalence ofpsychopathy, and the distribution and correlates of psychopathic traits in a representative national sample ofprisoners. Psychopathy was measured using the revised Psychopathy Checklist (PCL-R) in a second stage,cross-sectional survey of prisoners in England and Wales in 1997 (n=496). Poisson regression analysis wascarried out to examine independent associations between correlates and PCL-R total and factor scores. Theprevalence of categorically diagnosed psychopathy at a cut off of 30 was 7.7% (95%CI 5.2–10.9) in men and1.9% (95%CI 0.2–6.9) in women. Psychopathic traits were less prevalent among women. They were correlatedwith younger age, repeated imprisonment, detention in higher security, disciplinary infractions, antisocial,narcissistic, histrionic, and schizoid personality disorders, and substance misuse, but not neurotic disordersor schizophrenia. The study concluded that psychopathy and psychopathic traits are prevalent among maleprisoners in England and Wales but lower than in most previous studies using selected samples. However,most correlates with psychopathic traits were similar to other studies. Psychopathy identifies the extreme ofa spectrum of social and behavioral problems among prisoners.</p