The purpose of this study was to investigate the difference between personality traits and mental immunity of addicts and non-addicts. In so doing, forty addicts and forty non-addicts were selected using simple randomization sampling. The instruments employed to carry out the study was NEO-FFI questionnaire and Mental Immunity Questionnaire. The data were analyzed using Pearson's Correlation Coefficient, Regression and Independent t-test. The results of the study showed that there was no significant relationship between personality traits and mental immunity of the addicts. Among predictive personality variables of addiction, only responsibility taking has a strong predictive power. However, there was a significant relationship between those variables in non-addicts. The correlation coefficient of personality traits and mental immunity of non-addicts indicated that there was a significant relationship between mental immunity and responsibility taking at the level 0.05. Furthermore, there was negative correlation between mental immunity and openness at the level of 0.01. In addition, there was difference between addicts and non-addicts in terms of flexibility, openness and mental immunity.
