Abstract Japanese rheumatologists consider bucillamine (Buc) to be a useful disease-modifying antirheumatic drug (DMARD) and often give Buc to patients with rheumatoid arthritis (RA) prior to administering methotrexate (MTX). However, no large studies on the efficacy and safety of Buc in RA patients have been published in English to date. We therefore investigated the clinical course of RA patients treated with Buc and compared the results with those for patients treated with MTX to evaluate and confirm the place of Buc in therapeutic strategies for RA in Japan. Our results suggested that Buc should be given to patients with moderately active RA either before or after the administration of MTX because its efficacy can be judged within 3 months and because serious adverse events are rare. Issues like the ability of Buc to prevent joint destruction and its efficacy and safety when combined with agents like etanercept require future study.