Catalase activity and malondialdehyde (MDA) content were measured in whole body and mitochondrial homogenates of the banana fruit fly, Zaprionus paravittiger, fed on control and butylated hydroxyanisole (BHA, 10 mM) mixed diets. Catalase activity increased during the reproductive period and decreased thereafter with age. However, the MDA content increased with advancing age in both sexes. In general, females exhibited higher catalase activity and lower MDA content as compared to their male counterparts. BHA feeding increased catalase activity significantly during all age intervals in both sexes. Mitochondrial fractions had lower catalase activity and lower MDA content than whole body homogenates. However, the pattern of changes was similar in both homogenates with age as well as on antioxidant feeding. These results suggest that BHA strengthens the defense mechanism of the insects by increasing catalase activity and reducing MDA content which may be responsible for increased longevity of insects.