A short pathlength cell for infrared spectroscopy of fluids at high pressure and temperature has been constructed and characterized. Though the upper pressure and temperature limits were not determined, the cell has been maintained for prolonged periods at 150 atm and 110 oC with no evidence of structural failure. The cell design is relatively simple and allows for external reflectance sampling of a thin layer of fluid (ca. 4 æm) at 30o incidence, with a resultant optical pathlength of approximately 10 æm. Further, the design permits spectral observation of one of two fluid phases contained within the cell, thus facilitating studies of two-phase phenomena such as solubility and partition equilibria. Applications to supercritical fluids, molten salts, and two-phase fluid systems are demonstrated, and the potential utility of the cell for spectroelectrochemical studies is discussed.