This report describes the Institute of Gas Technology's (IGT) research on tight sandstone cores from four wells. Samples from the Dakota Formation of the San Juan Basin well, Canyon Largo No. 256, were selected for comparison with the unpublished measurements by R.D. Thomas of the Bartlesville Energy Technology Center. The second well is the Mobil PCU F31-13G Well in the Piceance Basin, which is being tested under a Mobil Oil Company Department of Energy (DOE) program. The third well is the Natural Buttes Well (sec. 15, T 10S, R. 24 E.) Uinta Basin. The fourth well is the C-K Geoenergy Well DOE-GC1 (sec. 16, T 17 S., R. 24 E.) Uinta Basin. Permeability to gas was measured as a function of pore pressure, confining pressure, and partial water saturation in an attempt to estimate in-situ permeability of tight sandstones. Permeability to liquid was also measured as a function of net confining pressure, and mercury injection tests were conducted on samples to obtain capillary pressure curves. The permeability of tight sandstones was found to be strongly dependent upon net confining pressure and partial water saturation. Brine permeabilities were found to be lower than gas permeabilities extrapolated to infinite mean pore pressure for the cores studied. Under no confining stress, pore size distributions, measured by mercury injection tests, indicate that the majority of pore entry diameters range from 0.1 to 5 microns. 13 figures, 3 tables.