A rapid method of routine whole rock analyses of major and trace elements, using low dilution fusions, is described. The method is particularly suited to use with automated x-ray fluorescence equipment, and is effective for rocks which range widely in composition. Corrections for matrix effects based on a matrix of influence coefficients, the calculation of a mass absorption coefficient from major component data and Compton scatter methods are discussed; data are presented which demonstrate that all thee procedures can be used with low dilution fusions. Spectral impurities (pMcipaUy of Cu, Ni and Zn) which cause problems in some trace element analyses using low dilution fusions and may also affect pressed rock powder studies are investigated and a simplified correction procedure is proposed. Lower limits of detection, accuracy and precision for determinations of 20 elements, carried out using low dilution fusions, indicate that the low dilution fusion procedure is well suited to routine whole rock analyses of major and trace elements. ~ OHeyden