A consecutive group of 100 patients over the age of 40 years, who were operated upon for histologically proven acute appendicitis, were reviewed. Although there were no deaths, 36 had complications, of which 30 were related to wound infection. Thirty-one patients were found at operation to have perforation. Of these 100 patients, 13 could have had their appendices removed previously at the time of an elective laparotomy. The morbidity of incidental appendectomy was reviewed in 200 randomly selected patients, also over the age of 40 years, who underwent either elective hysterectomy or cholecystectomy. Half had an incidental appendectomy and the other half did not. The indication for appendectomy was the preference of the surgeon. There was no important difference in operative or postoperative problems in the two groups of patients. The authors conclude that incidental appendectomy is a worthwhile and safe procedure unless there are specific contraindications.