The Comprehensive Assessment of Psychopathic Personality (CAPP) is a new personality based instrument created by Cooke et al. (2004) to assess psychopathic personality symptoms in adolescent and adult populations. The current version of the CAPP is the CAPP-Institutional Rating Scale (CAPP-IRS). It was developed to assess psychopathic personality symptomatology in secure treatment facilities such as prisons, civil psychiatric facilities, and forensic psychiatric hospitals over discrete time periods. The rating of the symptoms that are described in the CAPP-IRS is based on the semi-structured CAPP-IRS interview, a file review and collateral information. The 33 symptoms are grouped into six broad domains of personality. For each of the 33 symptoms, a number of trait descriptive adjectives are given. Each of the adjectives are further specified by a definition of behavioural indicators relevant to institutional adjustment. The developers (Cook et al., 2004) claim that the CAPP has several advantages as compared to other measures of psychopathic personality. These are mainly thought to refer to the focus on personality pathology rather than on specific behavioural acts such as criminal behaviour, the comprehensiveness of the instrument and the dynamic concept. Due to the latter advantage, the instrument might be useful not only for the assessment of the lifetime severity of psychopathic personality symptoms but also for the assessment of the severity of symptoms over discrete time periods. The CAPP has already received international interest with several translations underway. Among others, there is a preliminary German translation of the CAPP-IRS (Köhler & Heinzen, 2009). The present study examined the reliability, validity, and practicability of the German version of the CAPP-IRS in a small sample of German adult male forensic psychiatric patients and adult male prisoners of a high security state prison. A correlational research design was used, based on a muliti-trait-multi-method analysis. The study included the evaluation of the relationship of the CAPP-IRS to a measure of psychopathy (PCL:SV), risk for future violence (HCR-20), trait anxiety (STAI-T) and normal range personality dimensions (NEO-FFI), and to measures of Cluster B personality disorders (SCID-II). The promising results of the study are discussed in light of the construct validity of psychopathy. Furthermore, initial experiences in the application of the German Version of the CAPP-IRS in institutional settings (forensic psychiatry and prison) are discussed critically. Implications for future research are provided. „We are delighted to see the progress that scholars in Germany are making with the Germany translation of the Comprehensive Assessment of Psychopathic Personality (CAPP). Their work makes a significant contribution to the growing international evidence for the validity and utility of the CAPP; we look forward to more exciting findings.“ Professor Dr. David J Cooke and Dr. Carolin Logan (Developers of the CAPP)