A leader, as one of the determiners in organizational direction and objectives, must be able to respond to development. Basically, leadership is a process of influencing activity in a group directed toward the achievement of one or several objectives. In the context of empowerment of human resources, in order to produce professional employees having high integrity, the presence of a standard is required, which can be used as a guideline by the organization in solving the problems. Such guideline is the organizational citizenship behavior which systematically directs the employees to improve their work commitment. The present research has been done in order to study the relationship between transactional leadership, transformational leadership and leadership styles of path-goal theory upon organization citizenship behavior of social security organization of Mashhad. The main purpose of the research is the description and explanation of organization citizenship behavior and identifying effect of leadership on it. Stratified sampling method has been used for selecting samples. Sample size was 98 persons who were staff of the organization in Mashhad in summer 2011. According to the results, by confidence of 95%, we can say that there is significant and linear relationship between transactional leadership, transformational leadership and leadership styles of goal-path theory. From the bivariate regression, the ratio of variation of organization citizenship behavior which is expressed by transformational leadership variable to determination coefficient is 0.722; the ratio of variation of organization citizenship behavior which is expressed by transactional leadership variable to determination coefficient is 0.529; the ratio of variation of organization citizenship behavior which is expressed by leadership styles of path-goal theory variable to determination coefficient is 0.553. The results obtained from multivariate regression showed that (OCB) = 6.907 +0.184X1+0.277x2 -0.083x3; where OCB is the value of dependent variable of organization citizenship behavior; X1, idealized attributes factor by coefficient 0.184; X2, idealized influence factor by coefficient 0.277; X3, management by exception (passive) factor. Thus, it can be concluded that transformational leadership has more dominant impact in setting up the organizational citizenship behavior. Key words: Transactional leadership, transformational leadership, organizational citizenship behavior.