The search for alternative energy sources is presently at the forefront of applied research. In this context, thermoelectricity for direct energy conversion from thermal to electrical energy plays an important role. This paper is concerned with the development of highly efficient p-type Ge xPb 1-x Te alloys for thermoelectric applications, using spark plasma sintering. The carrier concentration of GeTe was varied by alloying of PbTe and/or by Bi 2Te 3 doping. Very high ZT values up to ∼1.8 at 500°C were obtained by doping Pb 0.13Ge 0.87Te with 3 mol% Bi 2Te 3.