ABSTRACT
Organizational commitment has been defined as [the relative strength of an individual's identification with and involvement in a particular organization]. Organizational commitment and factors that predict it has emerged as a promising area of research in recent decade for there is a strong evidence of link between high levels of commitment and favorable organizational outcomes. The main objective of this study was to investigate the relationship between the staffs personality traits [introversion - extraversion] and organizational commitment. This comparative - applied study was carried out in 2009-2010. The research population consisted of nurses working at Shahid Sad doghi and Shahid Rahnemoon hospitals. The sample [n=175] was selected by random sampling method. The data were collected by 2 valid questionnaires.organizational diagnosis questionnaire [ODQ] and Eysenck personality questionnaire [EPQ]. Data analysis was performed through SPSS[14] software using descriptive statistics and independent T-Test. The results of research indicated that the introvert and extrovert nurses are different in regards with their organizational commitment [p-v = 0/000]. Also, the organizational commitment was significantly different in both personality groups [introvert, extrovert] in terms of age group [P=0.003, 0.046] and job tenure group [p = 0/002, 0/042]. In the introvert group, organizational commitment was different based on the employment status [p = 0/017] but there was no difference in any group in terms of sex and marital status. The research results indicated that personality traits as a predictor of organizational commitment should be considered in human resources management