A methodology based on thermoporometry is proposed to evidence the hysteresis phenomenon observed between melting and solidification of a confined fluid. This method allows plotting hysteresis loops comparable to those observed for gas adsorption-desorption. It is applied to solids with various pore structure, size or connectivity. The hysteresis loops obtained have common features with those observed for capillary condensation suggesting the same type of classification. These are interpreted by similarities between the microscopic mechanisms of displacement of a phase by another in pore systems. (C) 2004 Elsevier B.V. All rights reserved.