A bed for hospital stays, of the type that can be articulated and comprising a plurality of sections which correspond to the regions of the back, buttocks, thighs and legs of the in-patient; one of the sections, the one that corresponds to the buttocks region, has at least one portion thereof which is movable and articulated to the section of the backrest and, when the backrest is lifted, is translated, exposing a curved element, which extends from the lying surface downwardly, and being inclined on the curved element contributes together with it to form a cradle for the buttocks region.