Reduced serotonergic (5-HT) neurotransmission has been reported in impulsive and aggressive personality disordered and offender samples. What is not clear is the relationship between 5-HT function and the North American construct of psychopathy assessed using the Psychopathy Checklist and its derivatives, which emphasizes the core interpersonal/affective as well as behavioural components of this syndrome. Fifty-one DSM-III-R personality disordered offenders who had a dynamic assessment of 5-HT function (prolactin response to 30 mg d-fenfluramine challenge) were rated on the Psychopathy Checklist: Screening Version based on interview and file data. The Psychopathy Checklist: Screening Version (PCL: SV) mean score in the sample was similar to other reports in European forensic samples. A three-factor structure best explained the PCL: SV data: arrogant/deceitful, callous-unemotional and impulsive-antisocial behaviour factors. 5-HT function did not correlate with psychopathy as a unidimensional phenomenon. The impulsive-antisocial component correlates negatively with 5-HT function while the arrogant/deceitful component correlates positively with 5-HT. In line with previous research findings, impulsive-antisocial conduct shows an inverse relationship with 5-HT function. Arrogant/deceitful traits correlate positively with 5-HT function and may be an adaptive component of psychopathy.