Enzymatic antioxidants such as selenium-dependent glutathione peroxidase (GPx), glutathione transferase (GST), glutathione reductase (GR), and superoxide dismutases (SOD), as well as the concentration of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA, an indicator of lipid peroxidation) were determined to identify which antioxidant enzymes participate in the efficient scavenging of ROS generated upon exposure to high doses of Cd² in fourth-instar Propsilocerus akamusi (Tokuna) (Diptera: Chironomidae) larvae after 72-h exposure. A significant increase in MDA levels and a change in GR and GPx activities in the Cd² -treated P. akamusi were observed. The MDA in 25.0 and 50.0 mmol/ liter treatments was significantly higher than that of the control dose after 72 h exposure. GPx activity was significantly induced by Cd² exposure only in the 50.0-mmol/ liter treatment with a 0.59-fold increase in the control. All doses of Cd² significantly suppressed GR activity compared with the findings for the control dose, with an inhibited rate up to 0.55-fold in the 25.0 mmol/liter Cd² treatment. SOD and GST activities were not altered. The results indicate that Cd² can induce oxidative stress as indicated by the changes in lipid peroxidation and antioxidant status. For P. akamusi, an increase in the dose that the threshold needed for defense (namely, MDA level and GPx activity) activation was achieved. From this, organisms can be hypothesized to enable cells to avoid oxidant stress up to a certain extent where damage is again measurable (higher Cd² concentration).