Test results from an experimental investigation undertaken at the University of Texas at Arlington on small-strain shear modulus response of residual and saprolitic soils sampled from a graniodiorite rock in the region of Antioquia, Colombia, are presented. Residual and saprolitic soil specimens were tested for different isotropic (total) stress states under natural and statically compacted conditions. Natural samples were tested in a conventional resonant column device, whereas compacted samples were tested in a novel resonant column device featuring self-contained bender elements, which allows for the simultaneous determination of shear wave velocity and small-strain shear moduli using both techniques. Results show that the Gmax increases with the level of confinement in a very distinctive fashion according to the weathering intensity of the test materials. Moreover, there is a reasonably close correspondence between values of shear moduli obtained from bender elements and those obtained from resonant column in compacted samples tested up to 200-kPa isotropic stress levels. Shear wave velocity values are also compared with those previously determined in the field in a similar weathering profile using down-hole testing. Test results were proven to be consistent with those reported by previous authors in similar soils and using different testing techniques.