Inductively coupled plasma-mass spectrometry (ICP-MS) is a powerful analytical technique, with considerable application to geochemistry. In this paper, we demonstrate the power of ICP-MS as a tool in petrogenetic studies. Data for 28 elements in seven U.S.G.S. basalt and andesite reference samples (AGV-1, BCR-1, BHVO-1, BIR-1, DNC-1, W-1 and W-2) are presented. Accuracy and precision (standard deviation) for 26 of these elements is either excellent (<3%) or good (3-7%). A detailed description of the ICP-MS technique we have developed is given. A simple HF-HNO3 dissolution in screwtop Teflon® bombs was used for sample preparation. ICP-MS instrumental sensitivity was measured by external solutions, with surrogate calibration for 4 elements. Matrix correction was made by use of standard addition. Naturally occurring internal standards (Rb, Y, Ce and Pb) were used to correct for instrumental drift between sample and spiked-sample measurements. We report data for the elements: Li, Cs, Rb, Sr, Ba, Zr, Hf, Nb, Ta, Y, Sc, U, Th, Pb and all 14 of the REE. In addition, the procedure acquired data for Be, Mo, W, Tl and Bi. Many elements in this array are crucial for the evaluation of petrogenetic models and source tracing. Herein lies the real power of ICP-MS - one technique, one dissolution, small sample size, good limits of detection, good to excellent accuracy and good precision for many geochemically important elements.