The subgroup of murderers with a combination of both paraphilic disorders (PAs) and paraphilia-related disorders (PRDs) (n=56) had the most lifetime cumulative sexual impulsivity disorders, more developmental problems, the highest persistent frequency of sexual activity, the highest number of previous sexual offenses, more sexual sadism, and compulsive masturbation. The findings suggest that PRDs should be systematically assessed in sexual offenders, so as to identify those offenders with the most lifetime sexual impulsivity disorders, which is more likely to be associated with a progressive and habitual pattern of sexual offending. The subsample with only PRD (n=29) had suffered more from childhood sexual abuse and showed more promiscuity, psychopathy, and alcohol problems. Sexual sadism was the most prominent diagnosis in this sample as well as in other studies of sexually motivated murderers. The study evaluated the psychiatric court reports of the 166 men who had committed sexually motivated homicide. PAs were diagnosed by the raters according to Diagnostic and Statistical Manual of Mental Disorders. PRDs were defined according to the criteria developed by Kafka and Hennen. This included repetitive nonparaphilic behavior and volitional impairment; personal distress; or impairment in social, occupational, or other areas of personal functioning. Other factors assessed were traumatization during childhood and criminal history. Four groups were compared: men without a PA or a PRD diagnosis, men with at least one PRD but no PA, men with at least one PA but no PRD, and those with a combination of both PA and PRD. 4 tables and 34 references