CEOs have a lot to worry about, but what are their greatest concerns? What keeps them awake at night? We interviewed 24 CEOs and asked them to name the biggest challenges facing their organizations. (Please note that titles used here reflect the positions the individuals held in 2013, when we conducted the interviews for a separate article). Their concerns fell into three broad categories: talent, operating in a global marketplace, and regulation and legislation. Given that CEOs set the tone and priorities for their organizations, it is important to understand what they interpret as the major challenges and opportunities.