Materials having hardness values above 40 GPa are usually referred to as superhard and are considered for application mainly in various fields of surface protection. This review follows this definition and deals with diamond, cubic boron nitride (c-BN), pure amorphous carbon, as well as hydrogenated (a-C: H) and nitrogenated amorphous carbon (CN x ). Thermophysical aspects of these materials are presented. First, the structure and chemical bonding of the superhard materials are treated. These are responsible for the high hardness and other interesting properties. Then, formation of superhard thin films is reviewed with special emphasis on thermodynamic conditions during thin film deposition. In the subsequent section, selected thermophysical problems are discussed, including c-BN as a thermodynamic stable phase at standard conditions, the thermal stability of carbonaceous films, and the thermal conductivity of diamond with respect to structural peculiarities of the films. Finally, thermophysical applications of superhard thin films are discussed with a few examples of diamond.