To overstate the importance of methotrexate in the contemporary management of rheumatoid arthritis would be difficult. It has achieved this distinction because of its efficacy and tolerability. This article reviews the data on the efficacy and toxicity of methotrexate, discusses caveats for clinical use, examines the use of methotrexate in combination therapy, and speculates on the future use of methotrexate in rheumatoid arthritis.