This experiment was conducted to clarify the effect of the temperature for grain filling duration on quality and taste of cooked rice cultivated in different region in Korea. In 2006 and 2007, 4 mid-late maturing group of rice varieties (Nampyeongbyeo, Ilpumbyeo, Junambyeo and Dongjin 1) were cultivated in 28 experimental plots of 27 different regions located in 8 provinces. The taste of cooked rice were positively correlated with 1,000 grain weight but negatively correlated with protein content of brown rice. Mean temperature for 30 days from heading was more closely correlated with grain filling and tastes of cooked rice than those for 40 days. Though, the optimum mean temperature for the best taste of cooked rice for 30 days after heading was 22.1 to 23.1℃ depending on varieties, in general, 1,000 grain weight and cooked rice taste were the highest in the mean temperature of 22.2℃ for 30 days from heading. But grains were poorly ripened in case of the mean temperature lower than 21.0℃ for 30 days after heading. Therefore, for the better taste of cooked rice in Korea, the developing new rice varieties and cultivation method should be focused to adjust the mean temperature within 22-23℃ during the period of 30 days after heading.