Abstract: There is disclosed new and improved multiphase thermoelectric alloys and a method for making the same. The alloys are disordered materials having a multiplicity of matrix crystallites separated by generally disordered grain boundaries containing transitional phases and grain boundary regions of various phases including electrically conductive phases having at least one phase having high electrical conductivity.The alloys are formed from a mixture of at least two separately prepared multiple element compounds preferably a first compound Bi.sub.10 Sb.sub.30 Te.sub.60 or Bi.sub.40 Te.sub.48 Se.sub.12 and a second compound Ag.sub.25 Sb.sub.25 Te.sub.50. These compounds while crystalline, have different crystalline structures. They themselves are polycrystalline and do not represent the most stable crystalline structure. The first compound has a rhombohedral crystalline structure and the second compound has a face centered cubic crystalline structure.