In rare penal cases, a defendant makes a claim that he or she was asleep at the time of an alleged crime. This article discusses a case of alleged sexsomnia where a man claimed that he had been asleep during a sexual encounter (rape) with a woman. The question that often arises during an investigation and in court is how complex a behaviour is someone able to perform and still be asleep? To assist the court in answering this question, forensic psychiatric experts may be appointed. But the experts were not present during the act and must therefore consider each case on the basis of the available information and existing research. This paper provides a brief overview of the research regarding sexsomnia. It will also discuss what kind of information is important to elaborate in these cases in order to clarify the premises for the experts’ conclusions to the court. Login using your SSSFT NHS OpenAthens for full text. SSOTP - You can request a copy of this article by replying to this email. Please ensure you are clear which article you are requesting.