The effect of low dose methotrexate (MTX) on postoperative complications in rheumatoid arthritis patients undergoing elective total joint arthroplasty was observed prospectively in 32 patients. Patients were assigned to discontinue MTX the week prior to and during the week of surgery (Group 1, n = 19) or to continue MTX throughout the perioperative period (Group 2, n = 13). Nineteen patients in Group 1 had 26 procedures, with no postoperative infections. Thirteen patients in Group 2 had 16 procedures, with 4 postoperative infections: 2 infected prostheses, 1 infected joint fusion, and 1 deep wound infection (P = .03). No patient had a postoperative flare of rheumatoid arthritis. Temporary discontinuation of MTX prior to joint arthroplasty appears to decrease the risk of postoperative infection.