A new secondary‐ion mass spectrometry technique is described for the quantitative analysis and depth profiling of rare gases incorporated in thin films and bulk solids. A Cs+primary‐ion beam incident on the sample surface was used to produce sputtered (CsR)+(R=rare gas) molecular ions whose yield was proportional to the rare‐gas concentration in the analyzed region of the sample. Depth profiles have been measured for Ar and Kr implants in single‐crystal Si, Ge, and GaAs wafers and a Kr implant in polycrystalline Ni. Detection limits ranged from ∼4×1017cm−3for Ar in Ge to ∼1019cm−3for Kr in GaAs where the sensitivity was decreased due to interference with (Ga2As)+ions at mass 217. The Cs+primary‐ion current density used in these experiments was 6 mA cm−2. It was not possible to obtain sufficiently high Cs+current densities in our system to observe R+secondary ions, although they were detectable using an O+2primary ion beam incident at 35–40 mA cm−2. The high current densities required in the O+2experiments, however, resulted in a correspondingly high sputter etching rate and hence a decrease in the depth resolution. Measurements of secondary‐ion intensities as a function of primary‐ion current density and secondary‐ion energy distributions showed that (CsR)+molecular ions were formed by surface‐ionization processes, while R+secondary ions were formed primarily by inelastic gas‐phase collisions involving rare‐gas atoms released from the samples with thermal velocities.