The objective of this review is to summarise the recent state of research on intake criteria for forensic psychiatry in Germany. Therefore, a systematic literature review was conducted on the legal basis of paragraph 64 of the German Penal Code for forensic psychiatry. Although the patients were very heterogeneous, relatively robust indicators were identified that may yield an unsuccessful therapy outcome. A younger age, previous delinquency, absence of an educational and vocational qualification, and personality disorders are the most robust indicators adversely affecting therapy in German forensic psychiatric institutions.