Abstract: This invention relates to a prosthesis brassiere for use by a woman who has gone through a mastectomy. The brassiere, which comprises one cup provided with a conventional filler and a second cup shaped for receiving and supporting the remaining breast, is characterized in that the cup for the remaining breast is provided along its entire periphery with detachable securing means comprising, for example, a zipper or a set of snap fasteners. The securing means makes it possible to easily and completely detach and remove the cup receiving and supporting the remaining breast from its peripheral carrying strap, and to reattach it to the same, while leaving the cup with the filler in place. Thus, the user can strip or cover the remaining breast, at will.