A pollen survey was conducted in Okayama for the 1972 calendar year. The results were similar to those of other districts of Japan. There were three pollen seasons: the tree, the grass and the weed season. Thirteen kinds of pollens were found in the Okayama area. In clinical studies positive skin reactions of asthma out patients were found in 29% of out patients for ragweed and 7% of out patients for Japanese cedar. Tow cases of pollen- asthma were confirmed allergologica in our clinic. One case of asthma was caused by ragweed, and the other case was due to Japanese cedar.