A Norwegian nation-wide sample of 1087 former adolescent psychiatric in-patients, 584 males and 503 females, were followed up 15-33 years after first hospitalization. On the basis of detailed hospital records from index hospitalization all were rediagnosed according to DSM-IV. The patient list was linked to the national criminal register and the diagnostic groups were compared as to gender-specific frequency of registered criminality. Next, the criminal career characteristics were compared in those with criminal records at follow-up, relative to mental disorder at index hospitalization. The prevalence of registered criminality, both overall and for specific types of crimes, differed significantly between diagnostic groups and between genders. In both genders criminal convictions were most frequent in disruptive behavior disorders and personality disorders. Among males, the lowest violent crime rate was observed in those with psychotic disorders. Males had more severe criminal careers than females, both quantitatively and qualitatively. The diagnoses and criminal profiles of the 10 most active criminals in the study sample were described closer, as were the 11 individuals found guilty of homicide.KEY WORDS: adolescent psychiatry; delinquency; violent crime; gender differences.