Aluminum toxicity can affect various plant processes; mainly root development which is not easily observed due to root growth habit. The objective was to evaluate root growth of mate when subjected to increased Al concentrations in the nutrient solution. Seedlings of three mate clones (C1, C2 and C3) were grown in nutrient solution added with 0, 100, 500, 1,000 and 2,000 μmol L-1 Al (AlCl3.6H2O) and a control without Al. Fifty days after transferring the plants to these solutions, dry matter of root, length and volume of roots of different diameters were evaluated. Al increase promoted root growth of all clones. Highest root length was observed for C2, followed by C3 and C1, for Al concentrations higher than 1,500 μmol L-1. The higher volumes were obtained by the clones C3, C2 and C1 with Al concentration off 2,000, 1,355 and 1,988 μmol L-1, respectively. The smaller root volume of C2 was obtained for Al concentration of 1,355 μmol L-1. The best fine root growth (dry matter and length) was obtained in Al concentrations above 1,500 μmol L-1. The results indicate that Al stimulates mate root growth, and the magnitude of Al tolerance is clone dependent.