Twenty commercial soybean cultivars from maturity groups IV through VIII were screened for nitrogen-fixation in a growth chamber using Rhizobium strains 3IlB 6,122 and combination of 6 and 122. The data on nodule number, nodule weight, shoot fresh weight, shoot dry weight, and acetylene reduction were recorded. Among twenty cultivars, 'Lee 74' (MG IV), 'Bay' (MG V), and 'Essex' (MG V) were identified as high N-fixers, based on more nodules and high acetylene reduction.