Fourier transform infrared (FTIR) spectroscopy combined with chemometrics of multivariate calibration of partial least square (PLS) regression is developed for analysis of total flavonoid content determination of Kasturi. Kasturi (Mangifera casturi) is one of the typical plant in South Kalimantan. Kasturi contain flavonoids. Kasturi has been reported ta have some biological activities such as antioxidant, immunomudalotory ; and antiinflamatory. PLSR was choosed to developed the prediction total flavonoid content. The calibration model was prepared by making the relationship between actual values of total flavonoid as determined using standard method spectrophotometrically in visible region (AlCl3 method) and FTIR predicted value aid with PLS. The developed calibration model was further validated using independent samples.The coefficient determination (R2) values for such correlation obtained are 0.998 and 0.995 for calibration and validation samples, respectively. The root mean square error of calibration (RMSEC) value of the developed model was 0.205% and the root mean square error of prediction (RMSEP) value was 0.831. Based on these findings, it can be concluded that FTIR spectroscopy combined with PLS can be used accurately and precisely to predict the total flavonoid content of kasturi with the regression equation of predicted value (y) = 0.979 x actual value as determined by AlCl3 method + 0.065. Keywords: FTIR spectroscopy, partial least square regression, Kasturi, Total Flavonoid,