Introduction & Objective: Adolescence is the most dangerous period  for  beginning of substance abuse. Providing an attractive educational program for increasing their knowledge cause a lower vulnerability to be damaged. 

Materials & Methods: This descriptive-Analytic study carried out in order to determine the knowledge of Kerman’s high school students for boys about the consequence of psychoactive substance abuse. According to the finding of the pilot study the sample size consist of 550 subjects. Sample were selected randomly through stratified, cluster and systematic sampling. The instrument for data collection was an investigator-made questionnaire which include two parts: part one consisting of demographic characteristics (11question), part two consisting of demographic characteristics of 23 multiple choice question to determine the knowledge about the consequence of substance abuse, such as nicotine, alcohol, cannabis, opium, heroin, LSD, steroid anabolic and tranquilizers.

Results: The total score of  knowledge was %20.7 (x=14.9±9.5) ,So the students had a insufficient  knowledge about substance abuses. The most score of knowledge is related to opium(%30), and the lowest score is related to LSD(%7). There was a significant difference between level of education and knowledge about all eight substances that mentioned (P<0.5).