This study explores the importance of the environmental factors on drug use and its effects on relapse. In this respect, the effects of peer groups and availability of drug are discussed in this research. Environmental factors have played a crucial role in both male adolescents drug use and relapse and could increase the likelihood of their becoming addicted to drugs and relapse (Taylor, Lioyd, & Warheit, 2006). An individual can have a variety of environments such as the family, community, school and friends, within each the risk of addiction and relapse might develop (Genetic science learning center, 2008). Furthermore, the adolescents have an influential need to spend more time with their surrounding environment; i.e. more time with peers and less with their families (Bezuidenhout & Joubert, 2003). Nearly 60% of Iran population is under the 25 and spending more time with friends is a prior preference among this young people. Also the adolescents” tendency toward using drugs is eased and reinforced with their availability since Iran is neighboring Afghanistan, a country of the greatest poppy and natural drugs with an annual production rate of almost 3000 tons (Farjad, 2000). Thus, one can assume that environmental factors play an important role in increasing the possibility of relapse after treatment. Therefore, this study considers two factors: peer groups and availability of drugs. The objective of this study is to examine the effects of environmental factors on relapse behavior among male adolescent opiate users in Kerman. In this research 226 adolescents between the ages of 13 to 20 were selected based on ten rehabilitation centers to answer the face to face interview questionnaire. Results indicated that there were significant relationships between these factors with relapse in adolescents. The study proposes some suggestions in order to prevent relapse after treatment in adolescents.