Abstract: Background and Objective: Simulated stevia beverages contain major diterpene glycoside, stevioside and rebaudioside A from Stevia rebaudiana . Methodology: The objective of this study was to develop FTIR spectroscopy in combination with multivariate analysis of Partial Least Square (PLS) regression for determination of stevioside and rebaudioside A in simulated stevia beverages. The PLS calibration was optimized by selecting wave number region capable provided the highest coefficient determination, R2 and lowest Root Mean Square Error Calibration (RMSEC). Results: Finally, the combined wave number range of 1161-2773 and 868-1041 cm–1 using Multiplicative Scattering Correction (MSC) followed by offset correction transformation spectra was chosen for stevioside determination with R2 and RMSEC value of 0.9954 and 3.40%, respectively. Meanwhile, selected wave number region at 791-1839 cm–1 without spectra transformation revealed optimal PLS regression for rebaudioside A determination with R2 and RMSEC of 0.9820 and 2.91%, respectively. Conclusion: The FTIR spectroscopy in combination with multivariate analysis of PLS regression could be used an alternative method for determining stevioside and rebaudioside A in simulated stevia beverages.