Ileostomy carcinoma is a rare malignant disease, which is seen primarily among patients, who have colectomy because of inflammatory bowel disease. The condition may develop decades after creation of an ileostomy and presents with reddening of the skin and adhesive problems with the stoma bag. These symptoms are easily confused with those of benign peristomal dermatoses. This is a case report of an 81-year-old woman with ileostomy because of colitis ulcerosa, where biopsies of the skin revealed ileostomy carcinoma. The patient underwent surgery, and the carcinoma was radically excised.