An assembly for attaching a replaceable wearing part to a leading edge of an implement includes a wearing-part holder configured to be received and fixed to a supporting surface formed at the leading edge of the implement and a replaceable wearing part. One of the wearing-part holder and the wearing part forms an attachment projection and the other of the wearing-part holder and the wearing part forms a corresponding socket. The attachment projection and the socket are provided with corresponding, cooperating guide portions. The guide portions of the wearing-part holder are formed as guide faces racing the supporting surface and being slanted relative to the supporting surfaces in a direction falling when moving away from the leading edge.