The objective of this study was to evaluate the antioxidant activity of tamarind seed extracts, sweet variety. The extracts were obtained by sub and supercritical CO2 different concentrations of ethanol. The extractions with pure CO2 were performed in the range of 20e50 C and 100e250 bar and with ethanol under the conditions of 50 C and 250 bar as well at 40 C and ambient pressure. The yields of extractions with pure CO 2 of better quality and quantity of antioxidant were obtained under the conditions of 50 C and 250 bar. However, the phenolic content of the tamarind seeds extract, sweet variety, obtained with pure ethanol at 50 C and 250 bar was superior to all the others, including the synthetic antioxidant butyl hydroxytoluene (BHT). Therefore, the ethanolic extracts of tamarind seed, sweet variety, are potential sources of natural antioxidants for the food industry