The aim of the present study was to determine whether pupillometry was able to identify and differentiate psychopathic personality traits in criminally responsible mentally disordered offenders (§ 21/2 StGB). Psychopathic disorder has not only behavioral, but also psychophysiological correlates, which may be evaluated by pupillometry. This might make it possible to diagnose psychopathy by means of a non-invasive method and in a further step to adapt therapeutic measures accordingly. Psychopathic behavior and personality traits were identified by means of the Hare Psychopathy Checklist-Revised (PCL-R) and offenders were divided into 4 groups with PCL-R scores of 0-10, 11-20, 21-30 and 31-40, respectively. Pupillometry makes it possible to objectively measure amplitudes of pupillary oscillations, which may serve as an indicator of central nervous activation/deactivation. The study at hand showed that the higher the PCL-R values, the smaller the amplitudes. Thus, it can be concluded that central nervous activation decreases with higher PCL-R values and psychopathy is associated with central nervous deactivation.