Some mutants and mutation-derived lines of 'S.J.2' and 'Sansai' soybean varieties were obtained after seed irradiation with gamma rays (Smutkupt, 1973; Smutkupt and Gypmantasiri, 1974). Among .them, three of S.J.2 lines, three of Sansai lines, including each control and one 'S.J.l' line (see Table 1) were selected to evaluate for seed yield, protein, oil, fatty acid composition, and other characteristics. Certain plant characteristics of these selected lines are shown in Table 1.