study aimed to examine the psychometric properties of 12-items Core Self Evaluations Scale (CSES) developed by Judge, Erez, Bono, and Thoresen (2003). Two hundred nineteen employees from Shahid Chamran and Jundi Shapoure medical Sciences Universities who were randomly selected were being surveyed. Cronbach’s alpha was 0.71 and item-total correlations ranged from.25 to.61, indicating high internal consistency. The validity of the scale was confirmed through multiple ways. First, in consistent with our expectation, exploratory factor analysis using principal components and varimax rotation showed that four core traits including self esteem, generalized self efficacy, locus of control, and neuroticism loaded significantly on a single factor: Core Self-Evaluations. Second, confirmatory factor analysis indicated that except for one item, all items of CSES loaded significantly on a single factor. Third, CSES was positively correlated with selfesteem, generalized self-efficacy, and locus of control, and negatively correlated with neuroticism that indicates convergent validity of the CSES. Fourth, CSES was significantly correlated with job satisfaction as an important variable that indicates empirical validity of the CSES. Fifth, hierarchical regression analyses revealed that CSES predict job satisfaction score beyond the core self- evaluations score and the four core traits. In sum, the results showed that the CSES is a valid and reliable scale for measuring Iranian core self evaluations.