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The objective of the present work was to develop, implement and validate an analytical methodology, based on the energy dispersive X-ray fluorescence spectrometry (EDXRF), technique for the direct, fast and simultaneous determination of arsenic (As), antimony (Sb), selenium (Se) and mercury (Hg) in samples of wild plants present in the region of Arica and Parinacota, located at the heart of the Atacama Desert. The method was optimized and validated in order to achieve the lowest detection limits. The validation plan of the proposed methodology considered the parameters of linearity, sensitivity, detection limits, accuracy, precision and matrix effect. Detection limits of 2.3, 3.6, 19.8 and 1.6mg.kg(-1) (dry basis) were determined for As, Se, Sb and Hg, respectively. Concentrations of these elements were measured in plants of different species growing in the region. It is concluded that, relative to conventional methods for determining these elements in plant tissues, the proposed methodology is a suitable analytical alternative that does not require steps such as sample dissolution or analyte transformation in hydride/volatile metal vapors for separation and/or extraction from the matrix prior to instrumental analysis.