The crop coefficient of rice were investigated using the Penman-Monteith method in Cheongju, in central South Korea. The mean actual evapotranspiration of rice was 4.8 mml d, and highest evapotranspiration of rice was 6.6 mml d in late August in 2001. The crop coefficient of rice showed 1.0 in early irrigation season, but over 1.5 in late irrigation season. The mean crop coefficient of rice in central area(1.16) was lower than that in southern area(1.49)