Introduction: Due to detrimental effects of work among managers of health and medical centers, this research was carried out to assess factors causing stress among managers of public medical centers in Tehran.

Method: This experiment was descriptive cross-sectional and was carried out by means of Luthans questionnaire. The subjects consisted of 94 managers of public medical centers in Tehran (all managers who were willing to complete the questionnaire). The results were analyzed using descriptive statistics.

Results: “Excessive sense of responsibility” was among the most important personal stressful factors, “problems regarding inflation and cost of living” among the most important familial factors, “low budget and lack of equipment and facilities” among the most important occupa-tional factors, and finally, “environmental pollution” and “unawareness of clients of social, cultural and economic standards” were the most important socioeconomic and cultural stressful factors among the managers of medical centers.

Conclusion: The most important stressful factors among managers of medical centers consist of low budget and lack of equipment and facilities.