An endoprosthesis for replacement of the ankle joint includes a component which is to be connected to the anklebone and which forms an upper slide surface a component which is to be connected to the tibia and which forms a lower slide surface, and a middle part. The middle part forms two slide surfaces which interact with slide surfaces on the tibial component and the anklebone component. In frontal section, the middle part is wedge-shaped with a wedge angle of between 1° and 12°.