In a number of recent cases, people charged with sexual offences have raised sexsomnia as a defence. Sexsomnia is a variant of sleepwalking, and the gist of the defence is that the accused’s conduct was involuntary, carried out while in an automatistic state. The law recognises two types of automatism: sane and insane.The former results in a complete acquittal whereas the latter leads to a special verdict of not guilty on the grounds of insanity or mental illness/impairment/disorder. Judges in Canada, England and Australia have relied on tests such as the internal/external and continuing danger tests to determine whether automatism is caused by a disease of the mind, and therefore insane. However, these tests are unhelpful in sexsomnia cases and the outcomes have been inconsistent. The recent Canadian Court of Appeal case of R v Luedecke provides a useful model for future sexsomnia cases.