”Tainung 4” soybean (Glycinc max (L) merr.) originated as an F8 plant selection from the cross (Nung-shih H-11 X PI 200492) in 1964. Hybridization, selection was made at Taiwan Agricultural Research Institute. It was evaluated in regional uniform tests begining in 1966 by Kaohsuing District Agricultural Station and cooperating Agricultural Station in Taipei, Hsinchu Tainan, Taitung and Hualian. Before release, it was designated Nung-shih 64-104. It has purple flowers, brown pubescence, yellow seed with light brown hila, and large seed (190-206 grams per 1000 seeds). It is resistant to lodging, and has determined with upright and breeder habit. Tainung 4 was registered in March 1970, and will be released in 1971. Taiwan Agricultural Research Institute will maintain breeder seeds. Tainung 4 was developed because of its high production and resistant to rust disease (Phskopsora pachyrhizi, Syd.) It yields over 59.9% more than Tai-ta-Kaohsung 5 in the spring crop, and 8% in the summer crop, throughout the country. In the winter crop, it yields equal to or above to Tai-ta-Kohsuing 5 in southern area where is the main production area in Taiwan. And the more severe the rust disease, the bigger difference was found in yield.