This study aimed to investigate of bisphenol A (BPA) on histopathological tissue (hepatopancreas and gills), immune ability (lysozyme activity), oxidative stress and antioxidant defence in crayfish (Pontastacus leptodactylus). Crayfish were exposed to BPA to various concentrations (0 (control), and 10, 50, 100 ??g/L) for 5 and 20 days in triplicates. Histopathological findings showed moderate to severe hyperemia and inflammatory cell infiltrations, irregular epithelial cell arrangements, degeneration, necrosis and sloughing at the cells, collapse of the hepatopancreas tubules and hyperemia, oedema and sloughing at the epithelial cells of gills. In addition to swelling of gills, accumulation of hemocytes in the hemocoelic space of the gill lamellae relating to dosage were noticed. Antioxidant-related enzyme activities which superoxide dismutase (SOD), Glutathione-S-transferase GST, and glutathione reductase (GR) activity in 10, 50, 100 ??g/L BPA group were significantly lower than control at 5 days (p 0.05). Lysozyme activity (LSZ) was no significantly enhanced according to control (p 0.05). These results suggest that the alterations in the antioxidant enzymes and the histological structure of the hepatopancreas, and gill tissue of crayfish can be used as potential biomarkers for risk assessment in aquatic ecosystem.