Numerous studies have been conducted to investigate the relationship between genetic factors and drug use tendency, many of which have shown a significant correlation between genetic factors and drug use, especially heroin and cocaine. The most important site of drug action is the brain, which contains a variety of nerve receptors. Dynorphins are opioid peptides derived from the prodynorphins precursor (PDYN). These opioid peptides are capable of binding to the three types of opioid receptors. Studies have shown that heroin and cocaine use is associated with increased PDYN gene expression in specific areas of the brain. In this study, we investigated the association between rs910080 polymorphism in the 3'UTR region and the number of VNTR sequences in the promoter region with the tendency of heroin use in 155heroin addicts and 150 control with RFLP method. Results showed a significant relationship between heroin abuse and CC genotype in rs910080 polymorphism (P = 0.001), but no significant relationship between VNTR promoter repeats and heroin abuse. Rs910080 polymorphism can be used as a distinguishing factor.