This study was conducted to investigate the effects of cadmium (Cd) exposure on biochemical factors in the hemolymph and hepatopancreas of the abalone, Haliotis discus hannai. The abalone were exposed to 0, 5, 10, 20 and 40 μg/L Cd for 4 weeks. The phenoloxidase (PO) activity was decreased in hemolymph of abalone exposed to 40 Cd μg/L for 4 weeks compared to the control (P < 0.05). The hemolymph enzymes, alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were markedly elevated in 40 Cd μg/L after 4 weeks. The hemolymph calcium concentrations were significantly decreased in 20 and 40 Cd μg/L for 4 weeks. Hepatopancreas superoxide dismutase (SOD) and catalase (CAT) activities were significantly increased by Cd. SOD was increased in both 20 and 40 Cd μg/L and CAT, in 40 Cd μg/L after 2 weeks (P < 0.05). These results suggested that the abalone SOD and CAT including PO may serve as a protective mechanism against oxidative stress by Cd. We conclude that a Cd concentration, 40 μg/L in water may curtail hemolymph homeostasis and anti-oxidative reactions in abalone hepatopancreas. From these results, these biochemical factors may represent a convenient method of monitoring heavy metal pollution in coastal areas.