The aluminum tolerance of four soybean cultivars was studied in nutrient solutions using different levels of this element combined with three different salt concentrations. The results showed that to separate the tolerant from the susceptible cultivars at 1mg Al3+/liter, the salt concentration of 1/10 of the complete nutrient solution was sufficient. The combination of 5mg Al3+/liter with 1/2 salt concentration can also be used considering the root length of the primary root as the parameter. The tops and root dry matter weight increased as the salt concentration in solution increased, independent of the Al3+ concentration. Higher Ca, Mg and K and lower Al concentrations were observed in the tops as the concentration of the salt in the solution was increased. This decrease in Al concentration was less evident for the cultivar Biloxi at both levels, 1 and 5mg Al3+/liter.