A healthy corporate governance culture is imperative in the banking sector where the retention of public confidence remains of utmost importance. In this regard, the board of directors are the essential fulcrum upon which the mechanisms of corporate governance and management rest. In Nigeria, however, poor corporate governance has been identified as one of the major factors in virtually all known instances of distress in banks. This is taking place against the backdrop of the existence of Code of Corporate Governance for organizations (including banks) in Nigeria. This contradiction is evaluated in this study which seeks to identify the challenges of corporate governance faced by directors in the Nigerian banking sector. Using the ex-post facto research design, this study draws on the views of executive and non-executive directors of banks in Nigeria, applying simple percentages, averages and rank order as statistical tools for the analysis of data. The study reveals the major challenges of corporate governance as the ineffectiveness of audit committees and lack of shareholder activism. The study recommends, amongst others that, shareholder activism should be legally required and encouraged and the level of such activism should be reported upon by the chairman in his statement and the auditors in their report. Similarly, audit committee should be responsible for hiring, firing and recommending the fees for non-executive directors and external auditors.