We have measured the yields of 90 keV40Ar+and V4He+sputtering of Mo and V samples by the use of a new radio-tracer technique. This technique involves activating the samples by high-energy charged-particle irradiation before sputtering, and using conventional γ-ray counting methods to analyze the material subsequently sputtered onto collector foils. We have also measured angular distributions of the sputtered material, and compared these results and our total sputtering yields with the predictions of Sigmund's sputtering theory. Further comparisons between our radiotracer results and those obtained for40Ar+sputtering of unactivated Mo and V samples, determined from elastic backscattering measurements using 12 MeV16O ions, show that the techniques give consistent results.