The glass-transition temperature (Tg) and crystallization temperature (TCr) have been determined for the system (60 x)V2O5–xSb2O3–40TeO2 with 0 < x < 10 (in mol%) using differential scanning calorimetry (DSC) at heating rates u = 3, 6, 9 and 13 K/min. The effect of the heating rate and the Sb2O3 content on Tg is discussed. It was observed that the tran- sition region shifts to higher temperatures when the measuring time is reduced (or, con- versely, when the applied temperature rate is increased). Using differential scanning calorimetry, the compositional dependence of Tg has been determined and so, an empirical equation has been deduced which relates the glass-transition temperature with the Sb2O3 content.