Highly competitive and continuous business changes in telecommunication industry make organizational citizenship behavior (OCB) strategically important. This research aims to test the impact of transformational leadership of the direct supervisor on working motivation of the employees. Does supervisor's leadership capability impact on employees' work motivation more intrinsically or extrinsically? The study was conducted in an Indonesian telecommunication company which provides television cable and high-speed internet services for the high-rise building in Java and Sumatra. It involved 199 employees as the respondents. The collected data was analyzed with structural equation modelling approach. The statistical test has proved that transformational leadership has a positive impact on work motivation and organizational citizenship behavior. The motivation – both extrinsic motivation and intrinsic motivation, impacts on organizational citizenship behavior significantly. Although transformational does impact on organizational citizenship behavior both directly and indirectly, but the working motivation does not play a mediating role in the relationship between transformation leadership and organizational citizenship behavior.