We investigated relations between physiological damages and gene expression and enzyme activities of superoxide dismutase(SOD) isoenzymes in leaves of rice (Oriza sativa L. cv. Ilpoombyeo) plants irradiated with a high-dose gamma-ray. Gamma-irradiation with 500 Gy caused significant decreases in the contents of protein, chlorophyll and carotenoid in the rice leaves by 24 h, especially reducing the chlorophyll contents up to 26% relative to the control. In contrast, gene expressions of SOD isoenzymes were kept higher in the irradiated leaves until 24 h after the irradiation than in the control and they started to noticeably decrease at 48 h, finally being lower in the irradiated leaves at 72 h than in the control. In the case of enzyme activities of SOD isoenzymes, some CuZn-SOD isoenzymes showed slightly increased activities until 48 h after the irradiation but at 72 h, all isoenzyme activities markedly decreased in the irradiated leaves below the control levels. In conclusion, 500 Gy gamma-irradiation used in the current study caused decreases in the contents of protein, chlorophyll and carotenoid as symptoms for physiological damages. Although such physiological damages were not directly related to the gene expressions and enzyme activities of SOD isoenzymes until 24 h after the irradiation, the damages at 72 h were reasonably attributable to their reduction.