This work is concerned with the effect of the rate of heating on the cold crystallization and fusion of poly(ethylene terephthalate) (PET) and of a blend of PET and 20% polystyrene (PS) by weight, by differential scanning calorimetry (DSC). Ten different heating rates, between 1C/min and 50C/min, were tested. The effect of heating rate on the crystallization and fusion behavior is similar for the neat PET resin and for the blend. The crystallization temperature is more than 60C higher and crystallization is 30 times faster when samples are heated at 50C/min, compared with the values obtained at 1C/min. However, the crystallinity developed is hardly affected by the rate of heating. The fusion process is only moderately affected by the heating rate. Complex, mostly symmetric crystallization peaks and simple highly asymmetric fusion peaks were observed for the blend. The results are discussed in terms of the factors affecting the kinetics of cold crystallization in blends