Three soybean cultivars were grown in nutrient solution to investigate their response to Mn using 0, 3, 6, and 10 ppm of Mn, as MnCl2.5H2O The results showed that 3 ppm was beneficial in increasing the dry matter yield of the above ground parts of the cultivars Davis, Santa Rosa and Biloxi. At 6 and 10 ppm of Mn, Davis and Santa Rosa were reduced considerably, and Biloxi showed reduction of dry matter only at the 10 ppm level. The weight of dry matter of leaves, or the above ground parts, height of the plant and the weight of the roots could be used as parameters to evaluate tolerance to Mn. On the other hand, root lenght was not a good indicator.