SUMMARYFrom a representative cohort, comprising 4296 adolescents born 1956–1961 and investigated 1972, the male subjects have been followed up after an interval of approximately 8 years. Of 2204 men between 19 and 24 years of age, 21 % were registered for crimes after the age of 15 years.The frequency of registrations for abuse of alcohol and narcotics is 7 % in the total male cohort (including the criminals) and 33 % in the group of criminals.There is a positive relationship between registration for abuse of alcohol and narcotics and severity of criminality. There is also a positive correlation between early onset of law‐breaking and severity of criminality.The frequency of absence from school on the class test day was not higher in the group of criminals than in the total male cohort, but within the group of criminals there is a slight positive relationship between absenteeism and severity of criminal