Basic thermoelectric p-type materials for the medium temperature range (600 to 900 K) are GeTe-based materials. Hot-pressed samples of (GeTe)1−x[(Ag2Te)1-y(Sb2Te3)y]x solid solutions with y = 0.6, y = 0.75 are prepared. Their thermoelectric properties (thermoelectric power S, electric conductivity σ and thermal conductivity K) in the temperature range 300 to 750 K are measured. The thermoelectric figure of merit Z = S2σ/K for some compositions in calculated. The best p-type new material is the composition (GeTe)0.8[(Ag2Te)0.4(Sb2Te3)0.6]0.2 with Zmax = 2.4 × 10−3 K−1 at about 700 K. [Russian Text Ignored].