The recently recognized high morbidity and unexpected mortality associated with rheumatoid arthritis (RA) has spurred new interest in more aggressive, early treatment of this disease. Methotrexate (MTX) has rapidly become the rheumatologist's drug of choice for serious RA because of its favorable efficacy to toxicity ratio and rapid onset of action compared with other second-line agents. The initial concerns about hepatic fibrosis and cirrhosis in psoriatic patients has subsided somewhat as long-term liver toxicity data are accumulating in patients with RA. Routine liver biopsy with incremental doses of MTX is no longer recommended. Potential for severe lung, hematologic, and infectious complications exists, mandating careful monitoring of RA patients taking MTX.