Objective: The current study was conducted to investigate the pattern of structural relations between deviant personality traits, risk perception and treatment motivation in people with substance dependency. Method: A descriptive- correlational method was used in this study. All the drug addicts referring to Ardabil centers of addiction treatment in second half of 2014 constituted the statistical population of this study. The number of 140 individuals from this population was selected via cluster sampling and responded to stages of change readiness and treatment eagerness scale, personality deviance scale, and cognitive appraisal of risky events (CARE) questionnaire. Results: The results showed that risk perception and three components of treatment motivation are negatively correlated with hostile thoughts, denigration of others, low self-confidence, dependency, submissiveness; however, risk perception was positively associated with the three components of treatment motivation. The results of regression analyses also revealed that 53% variance of recognition, 44 % variance of ambivalence, and 47 % of variance of step taking were explained by deviant personality traits. Model fitness indexed confirmed the path of deviant personality traits to treatment motivation via the mediating role of risk perception. Conclusion: The findings of this study suggest that low risk perception is one of the explanatory pathways for the relationship between deviant personality traits and treatment motivation.