A study of the influence of the moisture and the grain size on the gelatinization temperature (Tp1) of starch from four industrial maize flours as well as an unprocessed maize sample is presented. The gelatinization is a phase transition that can be observed using Differential Scanning Calorimetry (DSC), and it is manifest as an endothermic peak in the DSC thermogram. Results show that for 60, 65, 70 and 75% of moisture, the endothermic peak temperature increases from 70 to 75°C when the moisture increases, and decrease when the grain size increases from 250 to 420μm. A study of the gelatinization enthalpy (ΔHp) is also presented, this is related with the gelatinized starch present in the sample. The enthalpy decrease when the moisture increases and it decrease when grain size is increased.