We document changes in board characteristics in public US firms between 1997 and 2003. We find significant changes in board independence, committee independence, board size, interlocking directorships, director occupation and multiple directorships. Most of the changes occur between 2000 and 2003. In general, these changes appear both in small and large firms. However, changes in board size and in multiple directorships are statistically significant in large firms only. We find weaker trends in the financial stake of independent directors and in separating CEOs from the chairman position. In 2003 many independent directors have small holdings in the firms they direct and CEOs chair around two-thirds of the boards in our sample. Together, these results shed light on the types of board structures that have recently become the norm in US public firms.