Results of differential scanning calorimetry (DSC) under isothermal conditions on Se70Ge20Sb10 glass are reported and discussed. By using the Avrami equation the activation energy for crystal growth (EG) has been evaluated and the crystallization mechanism has been studied. The results indicate that the crystallization process is a one-dimensional growth. The calculated value of EG is 142.8 kJ mol-1 for Se70Ge20Sb10 chalcogenide glass