Corporate governance is mechanism use to improve firm performance and value because it reduces the level of expropriation of the company’s assets by the management and it also improves the level of expected cash flows that can be distributed to shareholders in form of dividends. The study examines how corporate governance has affected corporate performance under pre and post adoption of IFRS. The findings show that corporate governance is more effective in explaining and predicting corporate performance of listed deposit money banks in Nigeria after the adoption of IFRS better than before the adoption. In view of this, the study recommends that there is need to encourage application of IFRS principles by banks and other institutions to enhance corporate performance of deposit money banks in Nigeria.