This study investigates the prevalence, types, and impacts of bank fraud in Nigeria, comparing it with similar cases in developed countries. Employing a mixed-methods approach, the research combines quantitative and qualitative data from annual reports, academic articles, and case studies. By analysing these sources, the study identifies the factors contributing to bank fraud in Nigeria and evaluates the effectiveness of preventive measures implemented by Nigerian banks. The findings reveal that while Nigeria has experienced a significant increase in bank fraud cases, the average amount lost per case is lower than in developed countries. The most common types of fraud are ATM/card cases and electronic fraud. Factors contributing to bank fraud include inadequate internal controls, technological vulnerabilities, insider threats, and external pressures. The study also evaluates the effectiveness of preventive measures implemented by Nigerian banks, such as advanced technologies, internal controls, and employee training. The results provide valuable insights for policymakers, regulators, and banks in addressing the challenges of bank fraud in Nigeria.