This work focuses on the compositional dependences in parameters that govern the optical properties of (GeTe) x(Sb 2Te 3) 1−x amorphous alloys in the wide spectral range from above the phonons and to the inter-band electronic transitions. We studied the absorption edge fluctuations that are linked to the variations of the bandgap E g , the width of Urbach-Martienssen tails E U , the Tauc parameter B 1/2 , and average halfwidth < FWHM> of Raman bands in amorphous (GeTe) x(Sb 2Te 3) 1−x alloys at various temperatures. Obtained results reveal the compositional trends in the influence of the disordering on the absorption processes in studied alloys.