The refractive index of metal-chalcogenide glasses and their thin films of chemical composition CuxAs50Se50-x, for x=5, 10 and 15 at%, were accurately determined. This optical parameter was measured at room temperature, with an error of +/-0.01. Dispersion of the refractive index of massive samples in the wavelength range 650 - 900 nm was studied by the prism method. For the samples in the form of thin films, refractive index was determined by using interference maxima appearing in the spectra of optical transparency. The results indicate that the dependence of the refractive index shows a usual dispersion pattern and it increases with in increase in copper content in the sample.