A chain sprocket for link chains, for example, round link chains or profiled steel chains, has chain pockets for horizontal chain links. Chain pockets for vertical chain links are also provided. The chain pockets for the vertical chain links are separated from one another by teeth. The tooth flank surface of the tooth that a vertical chain link contacts under the effect of a load is dimensioned and profiled in a special manner. The dimensioning is such that up to a defined chain load the vertical chain link does not contact the tooth flank with its nose. A contact between the tooth flank surface and the nose of the respective chain link occurs only above a defined chain load.