This investigation was carried out to correlate BrimA values with total carotenoid content (TCC) in comparison to TSS (total soluble solid)/TA (total acidity) ratios and TA with TCC of six mango (Mangifera indica L.) cultivars: "Kaew," "Khew Sawoey," "Chok-Anan," "Nam Dok Mai," "Maha-Chanok," and "Nang Klangwan." Mature green mango fruits were selected based on having a specific gravity greater than 1.0 and then kept at 25±2oC with 70-80% RH. The sampling was carried out randomly on a daily basis until the mango fruits ripened. For all cultivars, the BrimA value, TSS/TA ratios, and TCC increased during the ripening process. The correlation coefficients (r2) suggested that TCC was highly related to BrimA values rather than TSS/TA ratios and TA in some cultivars. The best corresponding r2 values of BrimA and TCC were 0.88 and 0.99 for cv. Kaew and Nang Klangwan, respectively. Therefore, correlation between BrimA and TCC may be useful as an index for determining the ripening stage, flesh color, and sweetness of mango fruit.