In this study of 5851 Irish rural post-primary schoolchildren undertaken in 1970-71 by the Irish Cancer Society, the College of General Practitioners, the Economic and Social Research Institute and the Medico-Social Research Board, 1.2 per cent of the sample claimed to have taken drugs. In a comparable study of post-primary schoolchildren carried out in Dublin in 1970, 2.3 per cent of the sample said that they had taken drugs. Comparing this study to the Dublin study, exposure to drugs amongst post-primary schoolchildren appeared to be twice as great in Dublin as in rural Ireland. Exposure to drugs increased with age and was more marked in the case of boys. In both studies marijuana was the drug most commonly used. In this study, noticeable differences were found between those who had taken drugs and the total sample with regard to smoking and drinking habits, amount of pocket money and leisure activities.