The electrical conductivity of glasses in the Ag-As-Te-Se system is investigated by impedance spectroscopy for compositions lying along two joins, namely, Ag_0.2-As_0.4-(Te_x-Se_{1 - x} )_0.4 and (Ag₂Se)_0.2-[(As₂Te ₃)_x-(As₂Se₃)_{1 - x} ] _0.8. The transport numbers are measured using the Wagner method. It is found that, in the glasses containing silver in large amounts, the electron-hole conduction is predominantly provided by electrons rather than by holes, as is usually observed in chalcogenide glasses.