Ductal carcinoma in situ (DCIS) of the breast is thought to represent a number of biologically different processes, ranging in clinical presentation from a palpable mass to a mammographically-detected abnormality. The optimal management of DCIS is controversial. We reviewed our experience in 40 patients with DCIS, 26 with gross disease and 14 with microscopic disease. Treatment was by total mastectomy (n = 21), complete local excision (n = 16), and local excision followed by radiotherapy (n = 3). At a mean follow-up of 34 months (range 3-120), 35 patients (88%) are disease-free. All patients treated by mastectomy remained disease-free, but 3 patients (16%) treated by breast conservation surgery have had local recurrences. All local recurrences were in the same area as the original lesion, two manifesting the same subtype of DCIS and one an invasive carcinoma. The margins of excision were close to the resection margin in all cases that recurred. All four recurrences were successfully managed by mastectomy. Mastectomy is still the most secure and reliable management for DCIS, but pathologically verified wide local excision may be appropriate.