To analyze their isoflavones contents by HPLC analysis during two years on 60 collected old local traditional soybean varieties from various districts of Korea was conducted. There was a yearly variation in the seed isoflavon concentrations. The total contents on 5 isoflavones were in the range from 16.21mg/g to 25.21 mg/g and from 6.47 mg/g to 15.44 mg/g, in 1997 and 1998, respectively. Collected soybean from Gunsnsi-1(25.21 mg/g) in 1997 and from Gangjingun-3 (16.50 mg/g) in 1998 showed the highest amount of isoflavones as compared with other collected soybean varieties. The highest amount among 5 isoflavones was genistin as 48.45% and 49.73%, in 1997 and 1998, respectively, indicating the genotypic variation in seed isoflavon contents of local soybean cultivar. Our data suggest that it may be feasible for improving soybean variety with higher antioxiadtive activity and substances.