The Comprehensive Assessment of Psychopathic Personality (CAPP; Cooke, Hart, Logan, & Michie, 2004) is a new personality-based model and clinical assessment of psychopathy. This study was the first to examine the content validity of the English-language CAPP. Content validation is a crucial part of the development and refinement of any new instrument. Prototypical analysis was used to evaluate the representativeness of CAPP symptoms to the psychopathy construct in adults. Symptoms were rated by international mental health professionals (N = 132). Findings support good content validity of the CAPP, with most symptoms rated as highly representative of psychopathy. Domains relating to interpersonal style were particularly prototypical. Confirmatory factor analyses further suggested that CAPP domains are highly unidimensional. However, some CAPP symptoms may be weaker items in the model and further refinement is needed.