To determine the potential contribution of intermittent low-dose methotrexate (MTX) treatment (2-8mg/week) to postoperative complications, we studied 122 patients with rheumatoid arthritis (RA) who had 201 surgical procedures. The patients with treatment with MTX were allocated to two groups: Those who continued MTX (group A, 77 procedures) and those who discontinued MTX more than 1 week (group B, 21 procedures). The patients who had no treatment with MTX were allocated to group C (103 procedures). The incidence of postoperative infection, poor wound healing, and flare-up of RA was compared between the three groups. Postoperative infection occurred in 3.9%, 4.8%, and 3.9% in groups A, B, and C, respectively. Poor wound healing was experienced in 1.3%, 9.5%, and 7.8% in groups A, B, and C, respectively. At 4 weeks postoperatively, 3.9%, 14.3%, and 6.8% of flares were seen in groups A, B, and C, respectively. No significant difference was found in the patients with or without perioperative use of MTX. From these results, it is unlikely that continuation of intermittent low-dose MTX treatment increases the risk of postoperative complications in patients with RA. Continued treatment with MTX during perioperative period could suppress disease flares, especially in severe RA patients. © Japan College of Rheumatology 2006.