Blast resistance of one hundred and thirty-one rice cultivars bred in Korea was tested with thirty Korean isolates and twenty-two Philippines isolates using three screening methods. In the blast nursery conducted in Korea and in the Philippines, average disease index of rice cultivars were 4.6 and 2.2, respectively. Seventy-nine cultivars showed different resistance reaction in Korea and in the Philippines, and 19 cultivars showed the same resistant reaction in two locations. In the seedling test, Korean blast isolates displayed different levels of virulence. 93-093, a Korean isolate, was compatible with 90 cultivars whereas 97-057 showed a compatible reaction with 13 cultivars. Twenty-three cultivars showed high level of resistance against Korean and Philippines isolates but Chucheongbyeo, Heugnambyeo, and Manmibyeo showed susceptible reaction to all blast isolates. Through the sequential planting test in Korea and in the Philippines, Palgongbyeo and Seomjinbyeo displayed durable resistance, and Nagdongbyeo and Gihobyeo showed high level of disease infection over the planting time. These results indicate that blast isolates collected in two countries have different genetic background and number of compatible isolates should be considered in definition the durability of rice cultivar to rice blast.