The crystal structure of potassium hexafluoroplatinate (IV) has been determined. The structure is based on a hexagonal unit cell whose dimensions are a=5.76 Ǻ, 0=4.64 Ǻ. There is one molecule per cell and the space group is D33d-C3m. The Pt-F distance in the slightly irregular octahedral fluoro complex is 1.91 Ǻ.