Global increase in energy consumption and running out of fossil resources of the earth has stimulated scientists to search for new energy resources. The direct conversion of heat to electricity by using modern thermoelectric materials is nowadays considered as a possible energy resource which may have also impact on global warming. By assembling appropriate thermoelectric generators around the exhaust pipe of the automobile, some part of the waste heat may be recycled into electric power usable by cooling chamber or fridge of the vehicle. The major challenges in manufacturing this type of generators are cost and efficiency of thermoelectric materials. The efficiency of a thermoelectric generator through the dimensionless figure of merit ZT is associated with the electrical conductivity ?, the Seebeck coefficient ?, the thermal conductivity ?, and the temperature T. The ternary chalcogenides AgSbQ 2 (Q = Te, Se, S, …) are among favorite materials used in manufacturing thermoelectric segments that inherently have high Seebeck coefficient and electrical conductivity and low thermal conductivity, which may be further improved by doping impurities. Because of the similar scattering properties of the Ag and Sb atoms, various X-ray and neutron diffraction experiments have not been able to accurately determine atomic configuration of these systems, although all measurements conform the rock-salt crystal structure of this system. Hence we have considered five possible crystal structures in this work. In this study, structural, electronic, and thermoelectric properties of Age 2 crystal is investigated by using first-principles computations. The structural and electronic properties of Age 2 crystal is calculated in the framework of density functional theory and GGA-PBE approximation by using pseudopotential method. We have used the PWSCF code from the computational QUANTUM ESPRESSO package, in which the plane waves are used as the basis set for expansion of the Kohn-Sham wave functions. We used norm-conserving and scalar relativistic pseudo potentials. We considered five possible crystal structures of Age 2 compound ( ,,, and ) to find out its stable structure, equilibrium lattice parameters, Bulk modules, and cohesive energy. In the next step, the thermoelectric properties of different structures are calculated in the framework of the semi- ltr" Keywords: First-principles calculations, Age2, thermoelectricity, Seebeck coefficient, electrical conductivity, power factor, semi-classical Boltzmann traort theory, relaxation time