Longitudinal studies have consistently shown that psychopathy in adulthood has its roots in childhood. The psychopathy concept described by Cleckley (1976) involves interpersonal, affective, and behavioral aspects. Moreover, children who show low levels of anxiety respond more poorly to treatment. The aim of the present study was to assess psychopathy in 56 male juvenile delinquents with conduct disorder, treated in youth correctional institutions for severe offenders. We used a modified Psychopathy Checklist-Revised (PCL-R) that has been used for young people (Forth et al., 1990). Each participant received PCL-R assessments from one rater, based on the file information and an extensive interview. Twenty-eight participants (50%) were rated by the second rater. Both the ICC and Cohens’s kappa revealed that the PCL-R ratings were reliable: the ICC(2,1) of the PCL-R total scores was 0.90, F(27, 28) = 11.70, P < .0001; Cohen’s kappa = 0.64, P < .001. The final scores on the PCL-R showed that the base rate for psychopathy (defined as a score of 30 or more) in the sample was 59% (33 of 56 juvenile delinquents). The mean PCL-R total score for all 56 participants was 29.3 (S.D. = 7.8), and ranged between 12 and 40. The high rates of psychopathy found in juvenile delinquents with conduct disorder should alert clinicians to the necessity of psychopathy scoring, and shows that high-quality treatment programs are needed. Psychopathy is not currently considered when assessing and treating young people in state-administered observational and correctional institutions for juvenile delinquents in Sweden.