The Dutch criminal justice system (CJS) and the mental health system (MHS) have been standing alongside of each other for many years because in the Dutch criminal law legal provisions for psychiatric care are arranged in the MHS. Nowadays the prison services are aware of the possibilities of forensic treatment to prevent recidivism. As the mental health services could not fulfil their role as a psychiatric institution for all the mentally disordered offenders, more emphasis has been laid by the criminal justice system on the diversion of these offenders over differentiated units within the CJS itself. New developments are the purchasing by the CJS of forensic psychiatric care in the MHS, but paid by the system itself and under its own safety conditions.