Sixty patients with rheumatoid arthritis who were administered weekly low dose methotrexate (MTX) were retrospectively analyzed for their untoward effects of MTX by interviewing to the patients and by the medical records. Cough and sputa were the most frequent symptoms (23.3%) and gastrointestinal symptoms were the next (20%). Five of 60 patients (8.2%) showed liver function test abnormalities, and four (6.7%) exhibited transient exacerbation of arthralgia for several hours to a few days after MTX administration. Three patients (5%) suffered from interstitial pneumonitis. Hair loss was seen in 3 patients (5%), and headache, leucocytepenia, fever, skin eruption, abnormal taste, hemorrhagic cystitis, and flashing were experienced in a patient, respectively. Three (5%) suffered from fungal infection, and herpes zoster, sepsis, and osteomyelitis were experienced in each one patient, respectively. MTX was withdrawn in three patients (5%) because of cough and sputa the drug was withdrawn in other three patients because of the interstitial pneumonia, and was drawn in another three patients because of transient exacerbation of arthralgia. The drug was withdrawn in each one patient, because of nausea and vomiting, skin eruption, osteomyelitis, and sepsis, respectively. Overall, MTX were withdrawn in 21 patients (35%), and, of those, 13 patients (21.7%) because of untoward effects and 8 patients (13.3%) because of the lack of efficacy.