A method for producing a composite bathtub having at least one steel shell and at least one acrylic shell which are solidly joined to each other. A deep-drawn acrylic blank is first reverse-drawn over a core. An outer shell mold is then placed over the acrylic blank, at a certain distance from the acrylic blank. Once the outer shell mold and the acrylic blank are sealed off from each other, a reaction resin is injected into the space between the two shells. After the reaction resin has set, the outer shell mold is removed and the steel blank is positioned. The space between the steel blank and the acrylic blank is re-sealed and a polymer foam is injected into this intermediate space. Once the polymer foam has cross-linked, the composite bathtub is complete. One advantage of the method of this invention is that the acrylic shell and the steel exterior of the composite bathtub do not have to be identical in shape.