ABSTRACT This study primarily aims at finding out the impact of internal control system on the profit performance of commercial banks in Nigeria with an empirical study on Orient Bank of Nig. Plc and United Bank of Africa Plc. Internal control systems impact on commercial banks might be as a result of nonadherence to the system or stringent, inflexible adherence on the system. These two extremes will invariably have adverse effect on the profit performance of the commercial banks and as such the management will always try to strike a balance or trade-off for their profit maximization. The paper therefore tends to evaluate the extent of adherence to internal control system, its impact on the profit performance of OBN PLC and UBA PLC and control strategies to be adopted to revitalize or moderate the system. This project is divided into five (5) chapters – Chapter One: This is the introductory chapter that provides information about internal control system. This chapter gives insight of the problem identification, objectives and significant of study, hypothesis to be tested and scope and limitations of the study. Chapter Two: This is the Literature Review which makes good references to people that carried out the studies on internal control. It includes the importance and qualities of good internal control and also qualities expected of bank staff. Chapter Three: This includes Research design, scope and methodology. Chapter Four: This involves presentation and analysis of data collected. Chapter Five: This includes the Summary, Recommendation and Conclusions.