Eighty patients were operated upon with subcutaneous mastectomy and reconstruction with prosthesis. Seventy operations were performed on both breasts. The indications used were carcinoma in situ in a previous biopsy, pronounced epithelial proliferations on at least two previous occasions or recurring fibrocystic disease after at least two previous biopsies. Since the autumn of 1971, the operation has been performed as a one-stage procedure and we have had few complications. The appearance of the breasts was evaluated at review 3-60 months after operation. Most patients found the results acceptable or good. The mamilla always lost its sensibility, but the sensibility of the remaining skin of the breast sometimes returned with time. Most of the patients were well satisfied with the procedure and thought it better than any other sort of treatment. The tissues removed were thoroughly studied. Changes in the breasts were often bilateral and pronounced epithelial proliferation and carcinoma in situ were fairly common. Invasive carcinoma was found in 2 instances. The importance of the histologic examination of removed tissues is stressed. A regular follow-up of these patients is important for assessing the value and the risks of subcutaneous mastectomy.