The anti-lipid peroxidation (LP) activity and anti-superoxide formation (SOD) of new N-H and N-substituted indole derivatives were evaluated to determine their antioxidant activity. The results showed that compounds 1, 2, 5, 9 and 12 demonstrate considerable inhibition of lipid peroxidation of mouse liver homogenate. On the other hand, compounds 5 and 12 showed anti-superoxide formation activity at a concentration of 10(-4) M. Consequently, it can be concluded that these compounds exhibit important activity compared with reference compound alpha-tocopherol (vitamin E).