Rotifers are an important group of zooplankton in aquatic ecosystems that contain relatively high amounts of unsaturated fatty acids, proteins and peptides. Rotifers, especially Brachionus plicatilis species, are one of the important live food sources for maine fish larvae in aquaculture. The aim of this study was to evaluate the antioxidant activities of purified peptides from B. plicatilis. Antioxidant peptids of the B. plicatilis have been hydroylzed by Alcalase, α­Chymotrypsin, Papain, Neutrase, Pepsin, and Trypsin. Their antioxidant activity were evaluated by the free radical inhibitpory effect of diphenylpicrylhydrazyl (DPPH). Also the sequential chromatography method was used for extraction and purification of the peptides. The results showed that peptides obtained from the pepsin hydrolysate have a higher inhibitory effect than other peptides. Pepsin showed 58% inhibitory effect in 0.015 mM DPPH. Finally, the pepsin hydrolyzate constitutes were purified and isolated by gel-filtration chromatography (Sephadex G-250) and reverse-phase liquid chromatography on Eurospher C18 column (250×4.6 mm), respectively. The results of this study have been recognized the high antioxidant activities of extracted hydrolysates from B. plicatilis and their feasibility of using them in food industries as a food complement.