Cadmium in cacao is a key barrier to Colombian exports. Therefore, emergent technologies need to improve Cd testing capacity for cacao. Monochromatic X-ray fluorescence (MXRF) is a cost-effective alternative to conventional techniques such as inductively coupled plasma (ICP-OES/MS) for Cd quantification. MXRF can be applied to solid or liquid samples of cacao farming systems. Although this new technique has demonstrated high accuracy, it has not been validated against major analytical parameters to date. Therefore, the aim of this study was to demonstrate MXRF suitability for cacao and liquid culture samples. The method was validated using soil, soil litter, root, stem, leaf, pod, nib, shell, and Luria-Bertani microbial culture medium. The robustness, limit of quantification (LOQ), trueness, repeatability, intermediate precision, and reproducibility of Cd testing were assessed. Cd correlations between MXRF and ICP was performed using 363 field samples from cacao. The statistical analysis showed a Pearson correlation coefficient between 0.96 and 0.99 and a recovery percentage between 74.8 and 129.9 % for MXRF in comparison to ICP. The robustness parameter identified appropriate laboratory and field pretreatments. Likewise, the choice of measurement time of 60 and 200 s was critical. The LOQ ranged from 0.124 to 0.148 mg kg 1. For the parameter trueness, the % R ranged from 90.7 % to 109.0 %. The Z’-scores for reproducibility ranged from 0.50 to 0.62. The validation demonstrated the suitability of MXRF for Cd testing in cacao systems and liquid media. The impact of this new technology on cacao and food safety is discussed.