Objective: This study is carried out in order to compare the personality traits between the men who were dependent to Opiates and methamphetamines.

Materials & Methods: This is a causal-comparative and Cross-sectional study. Eighty opiates or methamphetamine dependent persons referring to a rebirth center were recruited based on a judgmental sampling and were matched on demographic variables. For data collection, demographic and the NEO Personality traits questionnaires were used. The data collected were analyzed using t-test.

Results: Results showed that there was a significant difference between the mean scores of Neuroticism (N), Agreeableness (A) and conscientiousness (C) (P<0.05) in NEO Personality Inventory between two groups of men dependent to opiates or methamphetamine the level of Neuroticism in Opioid dependence was lower and level of Agreeableness and conscientiousness was higher in methamphetamine-dependent. Both groups had the similar status in terms of Extraversion and Openness to experience (P>0.05).

Conclusion: According to these research findings, there are significant differences between men's personality traits dependent to opiates and methamphetamine. This might be useful for prevention and screening individuals at risk and applying the type of therapy according to clients’ personality