Cerqueira MS, et al. - This systematic review assessed the validity of the Body Adiposity Index (BAI) in predicting body fat percentage (BF%) in adults. Using PubMed, Web of Science, Science Direct, and Scopus databases, two independent researchers performed a search for studies that used dual-energy X-ray absorptiometry as a reference method. Findings showed that the BAI indicates wide individual errors, in agreement with the reference method, and a lack of sensitivity in detecting the change in BF% over time. Sufficient evidence was found showing that the BAI does not present satisfying outcomes, and its use is not suggested for BF% determination in adults.