A version of thermoporometry dedicated to analyzing the pore network of expanding clays is proposed here. The blurred, wide Differential Scanning Calorimetry (DSC) peak obtained upon the melting of a frozen clay sample is processed by means of a deconvolution analysis based on searching for such a temperature distribution of “pulse-like heat events” which, convolved with the apparatus function, gives a minimal deviation from the observed heat flux function, i.e. the calorimetric signal. As a result, a sharp thermogram was obtained which can be transformed easily into the pore-size distribution curve. Results obtained for samples of two Clay Minerals Society Source Clays (montmorillonites SWy-2 from Wyoming and STx-1b from Texas) at different water contents indicate a greater resolution and sensitivity than that achieved by classical thermoporometry using the unprocessed DSC signal. Phenomena corresponding to the evolution of the pore network as a function of the water content have been detected in samples with large water contents subjected to free drying prior to the experiments.