A passenger ship includes at least one superstructure having several superposed decks. At least some of the decks include contiguous passenger cabins having an outer longitudinal passageway, which extends between the latter and the hull. Each outer passageway is at least partly closed along its longitudinal side opposite to the cabins. At least one of the opposite ends of each outer passageway is open. The floor which separates outer passageways of two superposed decks is at least partly slatted. The ship includes air-conditioning for the cabins, with discharge of the treated air from the cabins towards the outside world, via said outer passageways. The passenger ship ensures ventilation of the passageways along both longitudinal and vertical directions, respectively, and with the air-conditioning.