A novel demountable sample transfer system is described that permits movement of large (1 X 3 cm) samples into and out of ultrahigh vacuum without venting of the main chamber. The system is optimized for infrared reflectance and electrical resistance measurements, and incorporates several features not available commercially. Six electrical contacts are carried with the sample--four for in situ resistivity measurements and two for a thermocouple. A bayonet-type latching mechanism provides rigid and reproducible sample positioning, and optical access to the sample surface is not obstructed, even at the grazing angles necessary for surface infrared spectroscopy.