INTRODUCTION: Citizenship behavior in the field of management and organizational psychology refers to voluntary and informal behaviors and actions taken by employees in order to improve the functioning of the organization, go beyond the regular duties, and are carried out voluntarily without expectation of reward. This study analyzes the relationship between employee performance and Organizational Citizenship Behavior (OCB) in the RCS of Markazi province. METHODS: In this descriptive-correlational study, the statistical population includes all the employees of the RCS of Markazi province which 130 people were selected as a sample using the Cochran formula. In order to collect data, the standard OCB questionnaire of Organ (1988) and the Job Performance Scale of William & Anderson (1991) were used. The relationship between variables was analyzed using correlation coefficients and regression through SPSS-23 software in two descriptive and inferential sections. FINDINGS: According to the findings, among the 130 participants, 82 (63.1%) and 48 (36.9%) were male and female respectively; the age group of 31-40 had the highest frequency with 57 (43.8%); and 6-10 years of work experience, bachelor's degree level and under -a-contract employment status had the highest frequency with 36 (27.7%), 49 (37.7%) and 51 (39.2%) respectively. However, there are a direct and significant relationship between employee performance and citizenship behavior in the dimensions of "altruism", "conscientiousness", "civic virtue" and "curtsey". The correlation coefficient of organizational performance with the aforementioned dimensions is 0.368, 0.347, 0.233 and 0.397, respectively. CONCLUSION: The results showed that among the dimensions of OCB, "curtsey" and "civic virtue" have the highest and lowest correlations with the "performance" variable. On the other hand, the "chivalry" has no significant relationship with performance. Also, the effect of OCB on employee performance was significant, which can be said that the predictor variable (OCB) is able to explai
