Aluminum is a major phytotoxic mineral in the soil at low pH conditions. The effect of aluminum (Al) on root length, flowering time, dry matter production, and grain yield was examined using two tolerant, Pungsan (PS) and Geumgang (GG), and one susceptible, IR36, rice varieties to acid soil. Rice seedlings were subjected to two Al treatments (+Al, 150 ${mu}M$ of Al; -Al, 0 ${mu}M$ of Al) in solution culture, where pH was always adjusted at 3.5. PS and GG showed significantly larger root length than IR36 in +Al at 2 and 8 weeks after the treatment (WAT). Flowering time was delayed 9 days in +Al compared to -Al in GG and PS and 27 days in IR36. Dry matter weight and grain yield of GG and PS were also significantly higher than those of IR36 under +Al. The inhibition of such agronomic traits by Al toxicity was less in Al- tolerant varieties than in a susceptible variety.