Empirical data are lacking that answer the question of how sexual murderers detained in forensic mental hospitals can be differentiated from those sentenced to prison. Psychiatric court reports and national criminal records on sexual murderers detained in a forensic mental hospital (n=45) were compared with those of prisoners (n=89) regarding diagnostic, criminologic, and prognostic characteristics and criminal recidivism rates after detention. Sexual murderers detained in forensic mental hospitals were characterized by higher psychiatric morbidity and slightly higher risk of future sexual and nonsexual violence. They were released from incarceration less often than the prison inmates but did not show higher sexual or nonsexual violence recidivism rates than those from the prison group.