Pollinosis usually caused by the airborne pollen grains, is an allergical disease which causes snivel and sneeze. The author has studied on airborne pollen grains collected at Chong-ro district in Seoul about 15m from April 1975 to March 1976. The obtained grains were 4 spp. of Gymnospermae, 19 spp. of Dicotyledoneae and 10 spp. of Monocotyledoneae. The tree season ranged from March to June, Alnus, Pinus and Acer were prevalent. The grass season ranged from May to October, Gramineae were prevalent. The weed season ranged from August, Artemisia were prevalent and ragweed was found.