Cd contamination in irrigation water can imperil human health through food chain. In order to investigate the genotypic differences in Cd accumulation of rice, thirty-five rice cultivars of different cultivar groups (temperate japonica, tropical japonica, tongil, and indica) were grown with irrigation water containing 2 ppm Cd throughout all growing season under the field condition in 2007. At harvest, highly significant differences in Cd concentration in different rice parts (root, shoot, straw, grain, chaff, brown rice, rice bran, and polished rice) was found among rice varieties and rice cultivar groups. Cd concentration of polished rice ranged from 0.26 to 1.85 mg/kg. The total Cd accumulation of shoot varied from 0.69 to 7.87 mg/m2. Indica cultivar group showed significantly higher Cd concentration and accumulation compared to the other rice cultivar groups. On the other hand, the distribution ratio in polished rice was the highest in Tongil cultivar group. The large genotypic variation suggested the possibility of breeding low Cd accumulating rice variety.