This study examined the mediating effects of social capital between transformational leadership and organizational commitment in hospitals nurses'. The survey was conducted with 244 nurses working in a general hospital. The data was collected with the transformational leadership, social capital and organizational commitment and analyzed using the SPSS/WIN 21.0 and Amos 18.0. A positive relationship was observed between transformational leadership, social capital, and organizational commitment; social capital had a partial mediating effect of a transformational leadership and organizational commitment. To increase the organizational commitment, mediating between the head nurse' transformational leadership and social capital is recommended.