(57) A water-closet, particularly apted for vehicles, composed of two basic parts, i.e. a seat (1) with a tank or basin (3) for collecting the sewage and a base (2) with reinforcing means (9, 11) and complementary parts constituted by a support (4) and a reservoir (20) received within said support, the base (2) being internally provided: on the rear side, with a reinforcing rib (9) and a coupling (10) for a venting or exhalation piping, towards the front, with a wall or rib (11), having a curved outline, apted to delimit a space to receive a flexible tube for feeding water to the shower (13) which exits from the housing (8) of the seat, and with a flange (7) for connecting the exhaust pipe (6) of the tank (3) with the true and proper exhaust, two small doors (15, 16) placed on the sides of the base (2) permitting the access inside the base (2) for the installation and servicing, at least one of the small doors acting also as a toilet- peper roll-holder (16). The support (4), open at the bottom, is provided with holes (18) corresponding with the holes (14) of the base, and with a hole apted to receive in a sealed condition the exhaust pipe coming from the flange (7), on its rear wall two vertical channels (17) be ing provided, apted to receive the venting or exhalation pipe (10) and the pipe (12) feeding the water to the shower. The support (4) receives a tank or reservoir (20) , internally provided with small supporting columns (22), some suitable holes, which are only marked, permitting to connect, through a valve (24) the tank (20) with another reservoir placed below the platform of the vehicle, or directly with a culvert.