A sensitive vacuum microbalance was used to determine the sputtering yields for the argon‐silicon system over an energy range of 34–800 ev. Preliminary data for the ion bombardment of silicon with CO2was also obtained. Variation of the discharge voltage provided information on the relative sputtering effectiveness of Ar+and Ar2+ions. Extrapolation of the low‐energy data indicates a probable threshold energy of 15–20 ev. The sputtering data indicate that the target surfaces were clean and reproducible. The experimental method is shown to be well suited for sputtering studies.