Abstract: The invention is a cross-country ski which is useful for ski mountaineering. The cross-country ski comprises a ski body having a longitudinal slot in its underface, metal edges extending below the underface, a climbing surface fixed in said longitudinal slot, a first fastening means fixed in said longitudinal slot, and a detachable running surface. The longitudinal slot preferably runs the entire length of the sliding sole, i.e., the sliding surface of the ski. The running surface has a second fastening means fixed on its backside and preferably an element of a third fastening means at its ends. In the latter case, an element of the third fastening means is also present on the ski body. The running surface covers the entire underface of the ski between the metal edges and fits flush with the metal edges.