Three pieces of equipment are described that are used for thermal investigations at high pressures in our laboratories : a high-pressure differential scanning calorimeter (DSC) for experiments up to about 300 MPa, and two high-pressure differential thermal analysis set-ups (DTA) for measurements up to about 300 and 1000 MPa respectively. For each apparatus, characteristic results on one selected organic substance respectively (including plastic and liquid crystals) are presented and discussed, and references for additional applications are given.