To standardize the Neuroticism, Extroversion, Openness Personality Inventory (NEO PI-R), the Persian version of the test was prepared and administered to a group of Shiraz residents (N = 502). The means and standard deviations for the five main scales and the total 30 subscales are reporteed in this paper. The results of analysis for internal consistency and correlation coefficient showed high correlation between subscales and their relevant scale besides, facets of a given scale with facets of other scales that have not positive correlation were totally satisfactory. The revealed strength of the test in these respects. Moreover, Test-retest reliability assessment with the average of 6.7 months interval for the scales was also statistically significant (r=O.53 to 0.67). The comparison between means and standard deviations of the present sample and those of United States revealed that the two samples were different in neuroticism, openness, agreeability and conscientiousness but not in extroversion scores.