Ethyl chloroformate as activator was investigated for esterification of long chain carboxylic acids (oleic, palmitate, and stearate) with stigmasterol at mild temperatures. Optimal conditions for ethyl chloroformate activity were found under anhydrous and basic conditions at 4°C to room temperature. Esterification products were isolated and purified using preparative radial chromatography and characterized by GC-MS and 1H-NMR spectroscopy. The GC-MS analysis results showed a fragment of (m/z) = 676.8, 650.5, and 679.8, which are correlated with the molecular weights of stigmasteryl oleate, stigmasteryl palmitate, and stigmasteryl stearate, respectively. Another confirmation was done by 1H-NMR, showing a change of chemical shift of 3.5 ppm given by the stigmasterol’s third carbon atom (C-OH) was deshielded to 4.6 ppm as it turned into (C-OR). GC-MS and 1H-NMR spectra indicated that stigmasteryl oleate, stigmasteryl palmitate, and stigmasteryl stearate have been successfully synthesized, suggesting that ethyl chloroformate is a worthy alternative activator for stigmasterylester synthesis.