This study analyzed survival, locoregional recurrence, and reexcision rates after breast conserving therapy, based on the margin analysis technique used at the University of Florida, which incorporates frozen section analysis of shaved breast tissue from the lumpectomy cavity. A retrospective review was done of 257 patients who underwent 267 consecutive lumpectomy operations and completed radiation therapy at our institution. Margins in 189 patients were assessed using frozen section analysis of shaved margins from the lumpectomy cavity. Breast conserving therapy was performed for 220 (83%) patients with early breast cancer (T1 and T2 tumors) and 47 (17%) with ductal carcinoma in situ. With a median followup of 5.6 years, the crude locoregional recurrence rates for patients who had margins analyzed intraoperatively by frozen section analysis or margins analyzed by permanent analysis were 1.9% (3 of 157) and 3.1% (2 of 63), respectively, for early breast cancer and 15.6% (5 of 32) and 6.6% (1 of 15) for ductal carcinoma in situ (p=NS). Survival rates were 97% and 78%, at 5 and 10 years, respectively, for the early breast cancer patients, and 98% and 98%, respectively, for ductal carcinoma in situ patients. Permanent intraoperative frozen section analysis reexcision rates were 33.3% (26 of 78) and 5.8% (11 of 189). Regardless of the technique used for margin analysis, breast conserving therapy led to low locoregional recurrence relative to national figures, pointing to the importance of the technique of radiation therapy at our institution. Reexcision rate was reduced with the use of frozen section analysis.