A deck with an integrated gutter system includes at least two separated joists and a plurality of planks. Each plank includes longitudinal grooves, is disposed above and supported by the joists, has an undersurface which is juxtaposed with the joists, and is secured to the joists. The deck also includes a plurality of unitary channels. Each channel includes a pair of flanges which mate with longitudinal grooves of immediately adjacent planks. The mating of the flanges of the channel with the grooves of the planks provides the deck with an impervious gutter that extends between and along the two planks, and is located above the joists to which the planks are secured.