The slow isothermal crystallization of concentrated amorphous starch systems is measured by Modulated Differential Scanning Calorimetry (MDSC). It can be followed continuously by the evolution (stepwise decrease) of the MDSC heat capacity signal (Cp), as confirmed with data from X-ray diffractometry, Dynamic Mechanical Analysis, Raman spectroscopy, and conventional Differential Scanning Calorimetry. Isothermal MDSC measurements enable a systematic study of the slow crystallization process of a concentrated starch system, such as a pregelatinized waxy corn starch with 24 wt % water and 76 wt % starch. After isothermal crystallization, a broad melting endotherm with a bimodal distribution is observed, starting about 10ยฐC beyond the crystallization temperature. The bulk glass transition temperature (T g ) decreases about 15ยฐC during crystallization. The isothermal crystallization rate goes through a maximum as a function of crystallization time. The maximum rate is characterized by the time at the local extreme in the derivative of Cp (t max ), or by the time to reach half the decrease in Cp (t 1 โ2). Both t max and t 1 โ2 show a bell-shaped curve as a function of crystallization temperature. The temperature of maximum crystallization rate, for the system studied, lies as high as 75ยฐC. This is approximately 65ยฐC above the initial value of T g . Normalized Cp curves indicate the temperature dependence of the starch crystallization mechanism.