Complex resistivity was measured for samples of Westerly granite and Berea sandstone saturated with 0.01 M KCLaq. A four-electrode technique was employed to make measurements over a frequency range of 10-3 to 106 Hz and a confining pressure range of 0.2 to 200 MPa. When the electrical response was analyzed in terms of equivalent conductivity &sgr; ' and relative permittivity K', both of these quantities varied more with confining pressure for the granite samples than they did for the sandstone. In addition, both rock types exhibited large low-frequency dispersion of permittivity. While previous studies have measured the response of near-dc conductivity to changes in pressure, measurements of pressure dependence of the full complex resistivity &rgr;*(ω) provide greater insight into earthquake-related phenomena as well as induced polarization measurements and other remote sensing techniques.