Substance use disorders (SUD) have been shown to be more prevalent among persons with schizophrenia and among those with psychopathy than among persons in the general population. In addition, it is speculated that the reported association between SUD's and offending among men with schizophrenia is due to histories of antisocial behavior and traits associated with psychopathy. Both the characteristics of psychopathy and SUD's have been proposed as determinants of criminal offending in men with schizophrenia. This study examined psychopathy, as measured by the Psychopathy Checklist-Revised (PCL-R), and SUD's and offending from adolescence through adulthood among men with schizophrenia. It was hypothesized that among offenders with schizophrenia, the score on the PCL-R, not the presence of a SUD, would be associated with criminal offending. The study also examined the offending of non-mentally ill offenders with psychopathy, comparing those with and without diagnoses of SUD's. The study sample included 202 men convicted for violent offenses in Sweden and who were diagnosed with schizophrenia and 78 men convicted for violent offenses in Sweden and who were diagnosed with psychopathy. Among the offenders with schizophrenia, those with high scores on the PCL-R had been convicted for more offenses and for more violent offenses than those with low scores on the PCL-R. The results indicate that among offenders with schizophrenia, as among non-mentally ill offenders, high PCL-R ratings are associated with more severe histories of offending and violence. The findings suggest that among offenders with psychopathic traits, the traits, not substance abuse, are associated with criminal offending. Tables, notes, references