Systemic lupus erythematosus (SLE) is frequently accompanied by gastrointestinal symptoms. Although all parts of the gastrointestinal tract may be affected, colonic involvement is quite rare. Colonic ulceration, particularly in the rectum, is associated with a high mortality rate in patients with SLE, despite immunosuppressive therapy. While a standard regimen for treating rectal ulcers as a complication of SLE has not been established, combination therapy with steroids and immunosuppressive agents is necessary because of the associated high mortality rate. In this report, we describe a patient with SLE whose condition was complicated with ulcerative lesions in the rectum and sigmoid colon; the lesions were successfully treated with a combination of corticosteroids and tacrolimus therapy. Tacrolimus could be a useful additional or alternative modality for treating rectal involvement in SLE.