Twenty two rice cultivars were studied in nutrient solution in relation to their tolerance to aluminum toxicity, at temperature of 25 ± 1°C and 30 ± 1°C using five different aluminum levels in 8.3 liter pots with 330 seedlings/pot, under controlled growth conditions. The tolerance was measured taking into account the root growth in an aluminum-free complete nutrient solution after a previous aluminum treatment. With an excessive amount of Al3+, the primary roots did not grow at all and remained thickened at the tip, showing a typical aluminum injury. In nutrient solutions at a temperature of 25 ± 1°C the rice cultivars IAC-899 and IR-841 were sensitive to the Al3+ concentration of 10mg/l of Al3+; IR-43, IR-45 and IR-8 were sensitive to 20mg/l and the cultivars IR-42 and CICA-4 were sensitive to 40mg/l; IAC-435, IAC-164, Pérola, Batatais, Pratão Precoce, Blue Bonnet, IAC-120, IAC-47, IAC-1246, IAC-25, IAC-165, Pratão, Dou-ado Precoce and CICA-8 showed tolerance to 40mg/l. In nutrient solutions at a temperature of 30 ± 1°C all cultivars presented tolerance to the Al3+ concentrations of 5, 10 and 20mg/l of Al+3. The cultivars Dourado Precoce, CICA-4, IR-42, IR-43, IR-45, IR-8, IAC-899, IR-665-4-5-5 and IR-841 were sensitive to 40mg/l of Al3+. Under the same conditions the following cultivars were considered tolerant to aluminum concentration of 40mg/l: IAC-47, Blue Bonnet, IAC-1246, IAC-164, Pratão, Pratão Precoce, CICA-8, IAC-435, IAC-120, IAC-25, IAC-165, Pérola and Batatais. The rice cultivars under study were ranked into classes of aluminum tolerance: tolerant: IAC-435, IAC-120, IAC-47, IAC-1246, IAC-25, IAC-165, IAC-164, Pérola, Batatais, Pratão Precoce, Blue Bonnet; moderately tolerant: Pratão, Dourado Precoce and CICA-8; and sensitive: CICA-4, IR-42, IR-43, IR-45, IR-8, IAC-899, IR-665-4-5-5 and IR-841.