Introduction:Organizational citizenship behavior (OCB) is associated with major factors such as job satisfaction and organizational commitment and productivity. However, counterproductive work behavior (CWB) as a voluntary behavior of the staff runs counter to the organizational objectives and interests. This research attempts to determine the relationship between OCB and CWB in the headquarters departments' staff of Tehran University of Medical Sciences in Iran. Methods:This descriptive-analytical and cross-sectional research was conducted in 2015-2016 on 235 staff of Tehran University of Medical Sciences who had been selected via employing Cochran formula. The research instrument included Pudsakoff's OCB Questionnaire including five dimensions of Altruism, Conscientiousness, Sportsmanship, Courtesy and Civic virtue, and the CWB questionnaire developed by Fox and Specter. The validity of the questionnaire was confirmed through content and face validity measures while its reliability was confirmed via alpha Cronbach method. SPSS software was used for analyzing the collected data. Incidentally, the descriptive tables were presented using mean and percentages, while the analytical statistics were provided through Pearson Correlation and Spearman, T-test, ANOVA and Linear Regression Tests. Results:The OCB was measured to be over the average and was 3.58 ± 0.95, and the CWB mean was 3.58 ± 1.14.There was a negative significant correlation between CWB and OCB (P=0.03, r=0.382). The correlation analyses showed that 14% of the CWB variations could be associated with OCB. Conclusion:Since only as little as 14% of the CWB is associated with OCB, it seems that other intra-organizational factors such as organizational justice, managers' ethics and organizational requirements could as well impact CWB and thus warrant further research.