These proceedings of the Sixth CANMET/ACI International Conference on Durability of Concrete held in June of 2003 in Greece contain 69 papers on topics that include large girders subjected to alkali-silica reaction, effects of the moisture condition of concrete on steel corrosion, effect of mixing different sizes of synthetic fibers in concrete, durability of porous concrete, low cement-content shotcrete, and the risk of steel corrosion in recycled aggregate concrete.