The increase in mergers and acquisitions as a way of expanding business externally is a result of the growing trend of nations embracing higher levels of liberalization, globalization, privatization, and deregulation. This study examined the pre-post financial merger performance of commercial banks in Nepal in an effort to close a knowledge gap in the field. The research design used is descriptive; with a sample population of eight merged commercial banks in Nepal. To study the financial performance of merged banks, capital adequacy ratio, non-performing loan, spread ratio, net profit margin, return on assets, return on equity, earning per share, and cash to total assets ratio were examined. Among this variables there is positive change in capital adequacy ratio, return on equity and cash to total assets ratio, where as there is negative change in non-performing loan, spread ratio, net profit margin, return on assets, and earnings per share. From the eight sample banks, it appears that the merger and acquisition has positive impact on Global IME bank limited, Prabhu bank limited and Sanima bank limited, where as negative impact on NIC ASIA bank limited, Bank of Kathmandu limited, NMB bank limited, Laxmi bank limited and Mega bank limited. Further, in future the area of merger and acquisition will be vast. More and more banks and financial institutions will go under merger and acquisition. Therefore, it will be complex to study the financial performance of merged banks. Hence, the researcher or students should adopted more variables, for measuring the financial performance of concerned bank. For successful merger and acquisition, banks need to identify factors affecting the financial performance in the area of merger and acquisition. The outcome of this research could provide better analysis regarding the pre-post merger and acquisition changes on financial performance and could be beneficial to financial institutions, other academic researcher, management consultant, and financial consultant.