This study aims to examine the relationship between the success of organizational change realized in corporations and leadership behaviours (task oriented, relationship oriented and change oriented) and the potential impact on this relationship in case of mediating role of person-organization fit between the leadership behaviours and success of change. The subjects of the study planned for description and relationship searching purposes are comprised of 140 employees at different levels all of whom experienced the change process in 17 different companies which have already experienced organizational change in Kocaeli and its vicinity. The study has been conducted based on a survey benefiting from a number of scales including task oriented, relationship oriented and change oriented leadership behaviours, personorganization fit and success of change as a data collection tool. The findings of the study reveal that the leadership behaviours displayed by executives during change process (task oriented, relationship oriented and change oriented) have an impact on the success of change with relationship oriented leadership behaviours making the most significant impact in that regard. It is also concluded that person-organization fit has a mediating role between the task oriented leadership behaviour and success of change.