Amorphous Ge{sub 30}Sb{sub 10}Se{sub 60} chalcogenide thin films were prepared onto cleaned glass substrates using thermal evaporation technique. The structure of the as-prepared films was confirmed to be amorphous using X-ray diffraction. The optical absorption coefficient ({alpha}) for the as-deposited films was calculated by using reflectance and transmittance measurements in the wavelength range 400-900 nm. The optical constants (refractive index (n) and the extinction coefficient (k)) were controlled by Murman's exact equations. The effects of annealing temperature in the temperature range 300-658 K on the optical and electrical properties of the as-prepared Ge{sub 30}Sb{sub 10}Se{sub 60} thin films were discussed in details. It was found that both the optical band gap E{sub g}{sup opt} and the activation energy for electrical conduction {delta}E{sub dc} increase with increasing the annealing temperature up to the glass transition temperature (T{sub g}), followed by a remarkable decrease with the increase of annealing temperature above T{sub g}. The obtained results were interpreted on the basis of amorphous-crystalline transformations.