Summary: Cannabis is easily available in Nepal, large numbers of persons using it regularly. I have studied its effects on 226 persons who had been using it for a long time and in considerable amount. As a control group I used an equal number of men of matching age and education.Compared with the controls, the cannabis users had a poor work record, poor social and family relationships, a lack of interest in sex and a general loss of initiative and efficiency. However, there was no difference in crime rate between the groups.