This chapter presents a practical guide for thinking about the main aspects of board design – that is, size, composition and board structure. It provides a summary of the main roles and responsibilities of the board in practice. The chapter proposes a systematic process for thinking about variables that could affect a board’s effectiveness in fulfilling its duties and its capability to add value. It shows that boards of directors are under increasing scrutiny from financial markets and society as a whole. Regulation enforces certain structures in the design of corporate boards. For example, in certain countries, the minimum number of members is established by law. The starting point in the design of a board should always emerge from a process of strategic reflection on the medium and long term. In addition to the provisions established by laws, regulatory authorities and stock exchanges, the design of the board should help achieve the mandate.