Sixty-five soybean germplasm lines from maturity groups (MG) IV to VIII were evaluated for their acid (pH 4.4) and Al (6 ppm) tolerances by measur-ing their N2 fixing capabilities with USDA rhizobium strain 110 and mixture of strains 110, 6, and 122. Plants were grown in a growth chamber in nitro-gen-free nutrient solution for 35 days. Plant introductions from MG VI had consistently higher (~100%) relative root length in 6 ppm Al nutrient solu-tion than those lines from other MGs.