Shrimp processing discards are an important source of carotenoids, particularly that of astaxanthin and its esters. The crude carotenoids extract obtained by solvent extraction of shrimp processing discards, and its fractions were evaluated for their antioxidant activity by in vitro assays and in a membrane model system using PL liposomes. The results indicated the strong antioxidant activity of the crude extract and the astaxanthin-rich fractions obtained from the crude extract. The antioxidant activity of shrimp carotenoid extract indicates its potential for use as a natural antioxidant for use in food and biomedical applications.