Because modern geochemical laboratories can seldom have all new analytical equipment, it is clear that priorities must be assigned and choices made when selecting each new instrument. X-ray fluorescence (XRF) spectroscopy has come to play a vital role in this environment largely because it is a dependable, multielement, rapid method that covers a wide range of elemental concentrations, commonly with only one sample preparation. The following discussion centers on the role of modern XRF instrumentation in the resolution of geochemical problems. In order to present a comprehensive view of this role, this paper draws upon a great deal of information from numerous X-ray laboratories visited in the United States and Canada.