Randomized, controlled and double-blind study of 36 patients aimed at the evaluation of the efficacy and toxicity of MTX in the treatment of rheumatoid arthritis. Twenty-eight patients completed the study period: 14 in the MTX group and 14 in the placebo group. The patients treated with MTX presented a statistically significant improvement (p < 0.05) in pain, grip strength and functional ability when compared to placebo treated patients. Mild adverse effects were observed in 4 patients treated with MTX and in 2 patients treated with placebo. These findings support other studies and give to methotrexate a relevant position in the treatment of rheumatoid arthritis, owing to its convenient posology, beneficial effectivity and favourable toxicity.