ABSTRACT: Portable instruments based on X-Ray Fluorescence Spectrometry (XRF) have the potential to assist in field-based studies provided the data produced are reliable. In this study, we evaluate the performance of two different types of XRF instrument (XOS prototype, and Thermo Niton XL3t). These two XRF analyzers were evaluated in a laboratory setting, and data were reported for 17 elements (As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, Sr, Ti, V, and Zn). Samples analyzed (n=38) included ethnic herbal medicine products (HMP), ethnic spices (ES), and cosmetic products (CP). Comparison analyses were carried out using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). In general, results reported for Cd, Cu and Pb by the XOS prototype analyzer, and based on the instrument's