Somnambulism is one of the sleep disorders described in the literature, which is classified as NREM sleep parasomnia. It is also referred to as noctambulism or more commonly as sleepwalking. At the same time, incidentally, certain sleep disorders can be associated with the unconscious performance of activities and even acts leading to material damage, body injury or even loss of life of another person or people. Therefore, the aim of this paper is to present the difficulties in establishing criminal liability in the event of committing offenses in alleged sleep-related unconsciousness, when an episode of sleepwalking may constitute exemption from criminal liability. Information from the current medical and legal literature, both in English and Polish, was used when considering somnambulism in terms of criminal liability.