The primary concern on fertilizer recommendations on paddy soils in Korea is not high rice yield but high rice quality, sustainable rice yield, and less environmental loads these days. Based on soil survey data, the paddy soils in Korea were classified into six large management groups; productive, sandy textured, less paddified, poorly drained, saline, acid sulfate soils. In order to establish the optimum level of nitrogen fertilizer to improve the rate of head rice yield, a field experiment was conducted at 24 farmhouses throughout the country with nitrogen fertilizer treatment levels of 0, 50, 70, 90, 110, 140, 170 kg ha^-1 from 2002 to 2004. As the result of the experiment, the optimum rates of nitrogen fertilizer for improving head rice yield were 90 kg ha^-1 in productive, sandy textured, and poorly drained soils, 100 kg ha^-1 in less paddified soils, and 112 kg ha^-1 in saline soils which the content of sodium chloride in soil was below 0.1%. The optimum rates of nitrogen fertilizer were determined in view of head rice yield, protein content in rice, and palatability value.