The increasing incidence and biological heterogeneity of ductal carcinoma in situ (DCIS) of the breast have made the management of this entity challenging and controversial. This paper reviews data on the natural history of the disease and results obtained with various management approaches. Computerized MEDLINE search of articles related to DCIS published since 1966. Randomized trials were given higher value; however, because these were relatively scarce, retrospective studies and data published in abstract form were also included. The authors reviewed all sources critically. No formal statistical calculations were made. The incidence of DCIS is increasing, and a greater proportion of diagnoses are being made in asymptomatic patients. No data from randomized trials compare mastectomy and breast-conserving therapy for the treatment of DCIS. A large randomized trial comparing lumpectomy with lumpectomy plus radiotherapy showed lumpectomy plus radiotherapy to be effective for management of this disease. The presence of comedo necrosis and surgical margin status are frequently used as predictors of subsequent recurrence, although this practice is controversial. The risk for in-breast recurrence at 5 years after lumpectomy and radiotherapy is approximately 8%. With more refined molecular analysis, the relation of DCIS to invasive breast cancer will be better defined. Treatment strategies for DCIS have evolved, and lumpectomy followed by radiotherapy is an appropriate alternative for most patients. The use of lumpectomy alone in selected patients remains controversial.