Methotrexate has been used as an important alternative therapy in the treatment of various rheumatic diseases. Life threatening marrow suppression in end-stage renal disease patients undergoing hemodialysis or continuous ambulatory peritoneal dialysis has been reported. A 33-year-old woman with systemic lupus erythematosus undergoing chronic peritoneal dialysis developed severe mucositis and pancytopenia after low-dose methotrexate treatment for arthritis. The leukocyte count recovered after methotrexate was withdrawn but a leukemoid blood picture developed during her recovery. No evidence of leukemia was found on bone marrow biopsy. The leukocyte count gradually returned to normal with conservative therapy.