Galvanostatic polarization experiments are performed on the asymmetric electrochemical cell Ag\AgI\Ag1.92Te\Pt in order to determine the chemical diffusion coefficient of AgnuTe (1.912 < y < 1.920) at 160 degrees C as a function of composition, the latter being varied by coulometric titration. As the specimen shows comparable ionic and electronic conductivities (the electronic transport number is around 0.8-0.9), new evaluation formulas are given and applied to determine the chemical diffusion coefficient. Both polarization (switching-on) and depolarization (switching-off) experiments are carried out and the experimental data are evaluated in the range of the short-time behaviour of the diffusion induced polarization process. The chemical diffusion coefficient of Ag1.92Te decreases slightly with decreasing silver content with typical values around 0.002-0.004 cm(2)s(-1).