Abstract The subject of this work is to develop contact joints between a CoSb3 thermoelectric material and a copper electrode. The CoSb3–Cu junctions were produced by the resistance brazing (RB) technique in the atmosphere of protective gases (90% Ar + 10% H2), with the application of Ag–Cu metal fillers. The diffusion barriers (Ni, Mo, Cr80Si20) on the TE segments made of the polycrystalline CoSb3 were prepared by the magnetron sputtering method. The microstructure and the chemical composition of the joints were examined using a scanning microscope (SEM) with an X-ray energy dispersion analysis (EDX). The examinations of the electrical parameters of the joints such as: the Seebeck coefficient, resistivity, and current–voltage characteristics were performed by a scanning thermoelectric microprobe (STM).