Purpose: This study was aimed to investigate the effect of transformational leadership on citizenship behaviors with respect to the role of self-determination-based identification, supervisor: identification and organizational identification. Methodology: The present study is descriptive in terms of method and applied in terms of purpose. It is also considered a field study in terms of data collection. The data collection tool is questionnaire. The validity of the questionnaire was evaluated and confirmed by technical experts and experts of the hospital human resources department and, its reliability using Cronbach's alpha. The statistical population of the study is all the staff of Rasool Akram Hospital. Using Cochran's formula and simple random sampling method, 220 people were studied as the final sample of the research. Structural equation modeling and LISREL software were used to test the hypotheses. Findings: The results showed that employees’ identification (organizational identification, supervisor identification and self-determination-based identification) had a significant mediating role in the relationship between transformational leadership and organizational citizenship behavior. Conclusion: Finally, in order to promote identification with the aim of strengthening the citizenship behaviors of employees in this field of healthcare and treatment, practical suggestions were presented
