This paper focuses on primary prevention of drug addiction, in particular the primary prevention programs implemented in school environments. It contains the results of a quantitative research conducted using a non-standardized questionnaire method. The study objective was to identify differences in attitudes of a group of pupils towards the issue of drug addiction before and after they completed the school-based prevention program. The study found that after completing the school-based prevention program there was improvement in attitudes towards the issue of drug addiction in the specific group of pupils. The number of appropriate answers to the question "Alcohol makes people happy" increased by 18.82 %. respondents (62.70%) disagreed that they would adapt themselves if their opinion differed to the majority. The number of positive answers to the question "Smoking is addictive" increased by 13.66%; the number of positive answers to the question "Drinking alcohol is harmful" increased by 24.93%; and all respondents agreed with the statement that smoking threatens health.UDC Classification: 314/316, DOI: http://dx.doi.org/10.12955/cbup.v4.774