Four soybean cultivars, IAC-9 Forrest, Santa-Rosa and Biloxi were tested in nutrient solution with 0.11, 2, 4 and 6 mg/l of Mn. The results showed that after 15 days, on termination of the experiment, 2 mg/l was adequate to separate cultivars that were tolerant to manganese from susceptible ones. Among the cultivars studied, Biloxi and Santa-Rosa showed tolerance, IAC-9 was intermediate and Forrest very susceptible. At the 4 mg/l level of Mn considerable damage was observed in IAC-9 and Forrest, where as at the 6 mg/l of Mn caused drastic reduction of the dry matter of the above ground parts of all cultivars. The dry weight of the above ground parts showed to be a good parameter for measuring tolerance to Mn toxicity. On the other hand neither dry matter weight of the roots nor the lenght of the primary root were good indicators of Mn toxicity. Increase of levels of manganese in the solution caused increases in percentage of P and K of the tops and the concentration of Ca and Ma remained practically constant.