Abstract Miniaturization of components and other advances in technology have resulted in significantly increased availability of portable X-ray fluorescence spectroscopy (PXRF) units, leading to a boom in their use in a variety of fields. An unfortunate corollary, however, is that there has also been a boom in the publication of data of doubtful quality, based on misunderstandings of PXRF and the underlying physics of X-ray fluorescence. Many manufacturers sell the units as point-and-shoot black boxes, capable of generating usable data under a range of conditions but, in reality, all of the assumptions and limitations inherent in laboratory-based XRF systems still apply or are even amplified in portable units. This paper highlights some of the areas of highest concern to alert readers and practitioners alike, and provides examples of some issues that may arise during analysis.