A questionnaire investigation in 1969/70 concerning drug use among military conscripts constitutes the basis for a study of the course and outcome of drug abuse and of drug-related medical and social conditions. 19% of military conscripts from Gothenburg indicated that they had at some time used drugs compared with 11% in the whole country. Between 4 and 5% of the men in Gothenburg indicated current drug use. Of those with some drug experience, more than 40% had used drugs more than 10 times. Cannabis smoking predominated. These figures are probably an underestimate because of the pattern of selection for military service. Those who had used drugs had more frequently used solvents and also had more advanced habits as regards alcohol consumption and tobacco smoking. Their intelligence level was somewhat higher than others' but they were less well-adjusted at home and at school. They had more frequently been in contact with the police or the Social Welfare Administration and more often had nervous problems.