The construction site manager (CSM) is a key actor in the construction phase to cope with various kinds of dynamic resource constraints and to fulfill required project goals. Many leadership studies have been conducted in the manufacturing industry, but a little is known in the construction industry. In this paper an attempt is made to investigate current practices in leadership styles of CSMs in building construction projects in Thailand. It is found that the studied CSMs are perceived to use the directive styles most and the supportive style least by their subordinates. At the sites where the participative style is perceived to be taken, performance of the subordinate group is high. At the sites where the supportive style is perceived to be taken, the subordinates' job satisfaction is high. As determinants of leadership style, quality of finished products and ethics are particularly important. Personal attributes of an immediate subordinate such as work experience and knowledge are also significant.