Introduction: Every organization, including a hospital, bears its own climate which needs to be compatible with the needs of the personnel otherwise, the efficiency of the organization will be diminished. This study was aimed at investigating the organizational climate of the hospitals of Tehran University of Medical Sciences (TUMS).

  Methods: This was a cross-sectional, descriptive, and analytical study including all general teaching hospitals of TUMS. The sample of the study consisted of 354 employees of clinical wards, supportive, and paraclinical departments. The instrument of the study was Sussman and Deep’s organizational climate questionnaire employed to assess their attitudes towards the organizational climate of the hospitals. Data entry was carried out by Excel software and data analysis was performed by SPSS software using T-test, Anova, and Duncan statistical methods.

  Results: Less than half of the personnel believed that the organizational climate was favorable. Moreover, there was a significant relationship between organizational climate the three variables of age (p = 0.01), employment status (p = 0.012), and the job type (p = 0.007).

  Conclusion : Most of the employees, having showed positive attitude only towards role clarity and organizational communication effectiveness, had negative attitude towards the organizational climate of the hospitals. The administrators of these hospitals, therefore, should take measures to change the climates through establishing efficient reward system, transparent organizational procedures, etc.