The effects of variations in chromium and aluminum contents on the microstructure, phase composition, microhardness, and heat resistance of the γ/β cobalt-chromium-aluminum eutectic alloys were studied. The formation of the γ/β eutectic having a specific "feathery" structure in the as-cast state was established to be very sensitive to the variations in aluminum content and substantially less sensitive to the variations in chromium content. The position of the projection of the γ/β eutectic valley in the isothermal section of the Co-Cr-Al ternary system was refined. A good structural and phase stability and heat resistance of the eutectics at temperatures of about 1100°C allows one to consider these eutectics to be a promising base for the design of multi-component (γ+β) heat-resistant alloys and protective coatings.