The extremely variable composition of geological materials, particularly that of rocks and soils, poses an immense challenge to the accurate and precise multielement determination of trace and ultra-trace level constituents. Hence, it is not surprising that numerous geoanalytical laboratories leapt with both feet into ICP-MS in its early days, with promises of such features as simple spectra with few interferences, wide linear dynamic range, and detection limits in solution in the order of 0.01-0.1 ngþml-1. Inevitably, we have since learned to temper enthusiasm with caution, as fundamental and applied studies of matrix-induced interferences have evolved. However, new doors have been opened in geoanalysis by this technique whose ultimate power is yet to be fully exploited. Undoubtedly two of the most significant achievements to date lie in the determination of two groups of elements: precious metals and the REEs. The collective determination of Au and the PGEs (Pt, Pd, Rh, Ru, Ir, Os) by commercial laboratories has been the sole domain of NAA. Application of ICP-MS in this field offers the advantages of superior sensitivity for Pt, Pd, and Ru and rapid turnaround time without the necessity of lengthy decay periods. This technique has also found a niche in the determination of Au, Pt, and Pd following Pb fire assay where previously ICP-AES and AAS have dominated. As in other applications the critical factor affecting detection limits is the purity of the reagents used, not the sensitivity of ICP-MS. Biogeochemical exploration for Pt and Pd has now become a practical tool, owing to the reasonable quantity of sample required to attain adequate detection levels. This technique now reigns supreme in its proven ability to determine all REEs down to 1 ngþg-1 if a separation step is incorporated into the procedure. This capability together with abundance level detection of high field strength elements (e.g. Nb, Hf, Ta) is greatly facilitating tectonic interpretation studies. The application of surface and ground waters in geochemical exploration is yet to be thoroughly evaluated but the ability of ICP-MS to analyze waters directly and adequately for many trace elements assures it a key role. Research into the introduction of gaseous hydrides into the ICP mass spectrometer is currently active in an effort to improve detection limits over those offered by ICP-AES. These comprise some of the accomplishments reviewed in this presentation. Progress in the use of alternative sample introduction techniques and calibration strategies is also discussed.