Twenty-nine patients participated in a prospective study of the safety and efficacy of oral methotrexate in the treatment of refractory rheumatoid arthritis. Patients received a mean dosage of 12.4 mg weekly over a mean duration of 29.1 months. All patients had liver biopsies at baseline, 2 years, and annually thereafter. Patients improved significantly by all clinical measures of efficacy after 1 month; maximum improvement tended to occur after approximately 6 months of therapy. Radiographs showed improvement of erosive disease in 7 of 11 patients measured. There was a significant reduction in mean prednisone dosage. Four patients required an increase in the dosage of methotrexate after prolonged therapy, because of declining clinical response. Toxicity was noted at some time in 26 of 29 patients (90%), but reactions universally became mild and tolerable after adjustment of the dosage. No significant hepatotoxicity was found in 60 sequential liver biopsies, although elevated transaminase levels were noted at some time in 20 of 29 patients (70%).