The mathematical bases for modulated differential scanning calorimetry (MDSC) have been discussed. It is found that the amplitude of hear flow is a non-linear function of the thermal transfer coefficient, lambda, the modulation period, p, the heat capacity of reference, C-pr, and the heat capacity of a sample, C-ps. Therefore, the quantitative determination of the heat capacity of a sample is rather difficult if not impossible. From this point of view, MDSC does not offer any advantage over a conventional DSC.