Social capital plays essential role for development of strong long-term employee commitment. This paper presents a study to investigate the effects of some employees’ personal characteristics on all components of social capital. The study uses a standard questionnaire developed by Nahapiet and Ghoshal (1998) [Nahapiet, J., & Ghoshal, S. (1998). Social capital, intellectual capital, and the organizational advantage. Academy of Management Review, 23(2), 242-266.]. The study has accomplished among all employees who worked as librarian in Astane Quds Razavi main library in city of Mashhad, Iran in 2014. The study has concluded that although age, job experience, marital status and type of employment had no impact on social capital, gender played essential role on this survey. In other words, our survey has indicated that women presented more social capital than men did.