Introduction: There are many challenges to implement the knowledge sharing between the employees. It seems, the employees intend to hide their knowledge even though there are so many facilities in organizations. In the other way, knowledge hiding cause decreased of organizational productivity and benefits, specifically health care organizations and clinical laboratories. Therefore, this research was aimed to determine the relationship between organizational culture and the employees′ knowledge hiding of Tehran University of Medical Sciences clinical laboratories of hospitals and the other health care centers.

Methodology: This was a descriptive, analytical and cross-sectional research that induced among the employees of TUMS clinical laboratories. 256 of the employees were selected as a research sample by Morgan table technique related to appropriate allocation and randomly method. The research tool was two questionnaires, including Dennison′s organizational culture and knowledge hiding questionnaire. 220 of the employees respond to the questionnaires, and therefore the response rate was 80%. The data was collected and analyzed by SPSS version 22 and descriptive results showed by average and standard deviation, and analytical results reported by Kolmogrov-Smirnov, Pearson, Two-sample T, and variance analysis statistical techniques.

Findings: Most of the respondants were females, having BSc. degree, 6 month to 2 years and 11-to 15 years work experiences and without managerial position record. The average of organizational culture and knowledge hiding were at intermediate level, and there was reverse significant correlation between the organizational culture and knowledge hiding of the employees.

Conclusion: Promotion and improvement of organizational culture and its dimensions including organizational participation and collaboration, compatibility of the employees, and paying attention to mission of organization could decrease the hiding of clinical laboratories of employees′ personal and organizational knowledge.