Ascidians are a rich source of bioactive secondary metabolites.Phallusia nigra is a simple ascidian belonging to the family Ascidiidae found in plenty throughout the year along the Thoothukudi coast of India.Antioxidant activity was performed by DPPH (1, 1diphenyl-2-picryl hydrazyl) radical scavenging method for different extracts of Phallusia nigra which showed that the alcoholic extract of the animal on higher concentration possess better antioxidant potential when compared to that of the standard ascorbic acid.They exhibited strong antioxidant DPPH radical scavenging activity with absorbance of 0.1984 and 0.0553 for ascorbic acid and ethanolic extract respectively.The strongest antioxidant activity of ethanol extract may be due to the presence of flavonoids and phenols.