A simple and uniforme method for testing rice cultivars for resistance to Rhynchosporium oryzae in a glasshouse was developed. Leaves of 30-day-old plants grown in plastic trays were inoculated with 6- to 7-day-old mycelial disks and incubated under moist conditions for 96 hr. Lesion extension from the point of inoculation was used as a measure of resistance. Susceptibility of test cultivars relative to a standard check cultivar was calculated. Of 40 local and introduced rice cultivars screened, 21 showed relative resistance to one isolate of R. oryzae.