The performance of five soybean varieties whose seeds were inoculated with four different mixtures of Rhizobiumstrains was studied at Ribeirão Prêto, State of São Paulo. In the seed yields, Hardee was statistically equivalent to IAC-1 and superior to L-2006, L-571 and Bienville. Mineral nitrogen did not increase the seed yields and the small responses to the inoculants were not significant. Although the experimental field had never been cropped with soybeans, the nodule formation was very good in all of the plots, so that no increase due to the experimental inoculants was observed.