Several studies have paid attention to the relationship between psychiatric disorders and adolescent offending but few have distinguished different types of offenders, especially within the category of youngsters who have committed sex offences.To test for relationships between psychiatric disorder and specific offence category among young male offenders.Nationwide data were extracted from Dutch Forensic Psychiatric Services (FPD) files for five groups of offenders, as defined by their index offence: 308 violent sex offenders; 134 non-violent sex-offenders; 270 sex offenders against children; 3148 violent offenders and 1620 offenders charged with any crime other than interpersonal body contact crimes. They were compared on individual characteristics and psychiatric diagnoses according to DSM-IV criteria. Having a diagnosis of a paraphilia alone was exclusively associated with sex offending, therefore all such youths were excluded from further analyses. The OVERALS technique was used to explore possible relationships between offence, psychiatric diagnoses, sociodemographic and individual characteristics among the remaining young men for whom all pertinent data were available (n = 1894).Sex offenders constituted a distinct group of juvenile delinquents. Developmental disorders were more common among non-violent sex offenders and child molesters. Violent offences were more typical of delinquents from immigrant backgrounds.Group differences in types of psychiatric diagnoses may reflect differences in aetiological factors for the various types of sexual and other delinquent behaviour, and this would be worthy of further study.