Between 1981 and 1989, 3 of 134 patients with rheumatoid arthritis (RA) treated with methotrexate (MTX) developed clinically significant hepatic dysfunction and showed histologic evidence of severe liver disease (fibrosis and cirrhosis). Factors identified in these patients that may have been linked to liver toxicity included diabetes, congestive heart failure and Felty's syndrome. In the patient group that received a post-MTX liver biopsy, pulmonary fibrosis and obesity were significantly associated with hepatic fibrosis/cirrhosis. Severe liver disease may occur in patients with RA treated with low dose MTX (less than 3%). Early liver biopsy is recommended in selected cases.