Along with formation of hierarchical microstructures, which allow improvement of mechanical characteristics of Ti-Al-N, the most effective way for solving this problem is the introduction of additional alloying elements into Ti 1-x Al x N, that is, obtaining of quaternary, quinary, etc. solutions. In particular, the addition of elements of the IV and V groups (Zr, Nb, Hf and Ta) to the Ti 1-x Al x N coatings is very promising. So, Zr increases the oxidation resistance of the coatings, contributing to the formation of a dense protective oxide layer on their surface. In addition, the introduction of its small additives leads to an increase in the hardness of the coatings and the critical temperature of spinodal decomposition. Doping with Nb leads to an increase in thermal stability and ductility of Ti 1-x Al x N coatings, however, there is a slight decrease in their hardness. Hf provides the growth of hardness and thermal stability of Ti 1-x Al x N coatings, whereas the effect on their oxidation resistance is ambiguous. Finally, one of the most promising alloying element is Ta, which allows not only significant enhancing of the hardness, toughness and oxidation resistance of Ti 1-x Al x N coatings, but also increasing the temperature of formation of the AlN wurtzite phase up to 1200 • C, which ensures maintaining high hardness values up to this temperature. It is well-known that the properties of the multicomponent solid solutions strongly depend even on small variations of the relative content of the constituting chemical elements. To a large extent this is due to the changes in the electronic structure and chemical bonding of the transition metal nitrides caused by variations of their elemental composition. Despite the numerous experimental and theoretical investigations of the mechanical properties, solar selective characteristics, oxidation behavior, biocompatibility and thermodynamic stability of different ternary and quaternary TiN-based solutions, the quantitative analysis of the evolution of chemical bonding of these materials at an ab initio level was not thoroughly addressed. In the present paper, within density functional theory (DFT) calculations, we examine the evolution Figure : Supercell for disordered Ti 1-x-y Al x Ta y N constructed on the base of 2×2×2 cell of the cubic TiN with 25% of Al and 25% of Ta atoms randomly distributed on the Ti sublattice. The presented ball-and-stick atomic structure was created with VESTA. of electronic structure and the interatomic chemical bonding in multicomponent TiN-based solid solutions from TiN through Ti 1-x Al x N to Ti 1-x-y Al x Ta y N with different atomic ratios of Ti, Al and Ta, using crystal orbital Hamilton population formalism. We also discuss the effect of the chemical bonding on elastic properties of the TiN-based systems.