Aims Addiction is a physical, psychological, and social illness, where shocking behavior that has destructive consequences, repeats constantly. Addiction is one of the problems of human societies and combat this problem always many losses a lot of energy and money. Jealousy is an unpleasant feeling and inclusive. The nature and the core of jealousy is wishing and trying to lose favor others. Jealousy is one of the emotions that disrupt the normal functioning of a person’ s life are sometimes endanger her physical and mental health and it is almost important. Therefore, the aim of the present study was to determine the effect of jealousy on the causes of tendency toward addiction. Instruments & Methods This cross-sectional study was conducted on 100 male addicts referring to addiction treatment centers in Mashhad were selected using random sampling. The instrument was the jealousy and the tendency to an addiction questionnaire. The data were analyzed using SPSS 20 software and ANOVA, Pearson and Spearman correlation analysis. Findings The results depicted that the mean age was 32. 3± 8. 5 years and the mean duration of addiction was 10. 42± 6. 8 years. Also, the average scores of them were jealous of 102± 21. 5 and the average score tendency to addiction was 40. 3± 7. 6. Spearman correlation tests indicated that there was a significant correlation between the tendency to addiction and jealousy (p<0. 001). Conclusion The results suggest that jealousy can predict some addiction tendencies. Therefore, in order to reduce people’ s desire for addiction, it is recommended to implement religious, cultural, and educational programs.