This study presents two prototypes of calorimetric cells equipped with an in-situ mechanical agitation system, which allow performing experiments under pressure. The first system presented, called MIXCEL®, was developed for macro-calorimetry analysis (experiments carried out with a BT 2.15 Calvet Calorimeter from Setaram Instrumentation) and already patented in 2012 1. Concerning the micro-calorimetric agitated cell (called MICROMIXCEL®), it is the first time that such a system will be presented. This novel prototype was developed for micro-DSC analysis (experiments carried out with a DSC VII from Setaram Instrumentation). Both technical aspects, and results obtained at macro and micro scale with polyphasic complex systems (gas hydrates or ice slurries), are presented and discussed. The use of such calorimetric cells opens a wide range of possibilities for systems which must be analyzed in both pressurized and agitated conditions