The place of banks in the growth and development of a country can never be displaced. It is therefore obligatory to ensure the continuous survival of the banking sector. Merger and acquisitions is perceived to be a catalyst in ensuring this phenomenon. Mergers and acquisitions became predominant in the Nigerian banking industry in year 2005 in response to the central Bank of Nigeria’s policy to increase the minimum capital requirement of the Nigerian deposit money banks from N2 billion toN25 billion. At that time, more than half of the deposit money banks were involved in merger and acquisitions. This study examines the impact of merger and acquisitions on bank performance in the Nigerian banking industry from 2000 – 2013. The ordinary least squares method was used to examine the significant effect on bank performance for both pre- merger and post-merger periods to find out if bank mergers produce any performance gain as well as its effect on efficiency of operations. Evidence proves that mergers and acquisitions have a significant effect on bank performance and efficiency of operations. We therefore recommend that deposit money banks should utilize the impact effectively so that they could play their role well in the growth of the real sector.