The invention relates to a bladder prosthesis for subcutaneous implantation, comprising a flexible and substantially tubular liquid container (1) with a wall composed of at least two material layers and a front face and rear face, wherein at least the front face has stabilizing elements. A non-return valve is arranged on each of the openings (2) for the admission of liquid, or a non-return valve is arranged on one of the openings (2) while the other opening (2) is closed with a stopper. According to the invention, a manually activated valve element, or a hose element containing a manually activated valve element, is arranged on at least one opening (3) for the discharge of liquid. The openings (2 and 3) are designed such that they are suitable for the fastening of valve or hose elements. The outer layer (4) of the liquid container wall consists of biologically inert material, and the inner layer (5) is smooth and consists of a chemically inert material. According to the invention, the material layers of the liquid container wall are cohesively interconnected.
