The cases of mental disorder simulation in order to avoid criminal liability are quite often in both medical and law practice. We studied 40 men that were referred to forensic psychiatric assessment. The first stage of the assessment was conducted when a person was in a psychiatric department of a hospital or at the detention facilities. The second stage implied the investigation of procedural documents after the court decision. We have identified the following signs of mental disorder simulation: a) significant difference in the behavior of the person during the conversation with a doctor or an investigator upon interrogation and usual behavior in a ward of a medical institution or in a jail; b) petition for psychiatric assessment in the absence of evidence of mental disorders in the past; c) absence of sleep disorders.