Ten compositions were prepared in the systems As:Se:Te and As:S:Te. Nine of these compositions were amorphous in structure. The resistivities and Seebeck coefficients of these materials were measured as functions of temperature. The resistivity varied exponentially with temperature, while the Seebeck coefficient varied linearly. At 298°K, the resistivity values for the amorphous samples ranged from 4.7×104−2.5×1013ohm‐cm, while the Seebeck coefficient values ranged from 830–1625 &mgr;v/°K (ptype). At any temperature, the resistivity decreased with increase in tellurium content. For the amorphous materials, the thermal conductivity values ranged from 2.4–4.4 mw/cm‐°K.