We reviewed 199 radiated patients at our institution (201 breasts treated) and its affiliates treated between 1978 and 1989. Of these. 157 were Tl and T2 invasive breast careinoma. Our intent was to retrospectively compare the results of those who received standard doses of 4,500 to 5.000 cGy to the breast to those that received an additional boost to the surgical bed to a dose totaling at least 5.500 cGy. There were a total of 5 local recurrences in 159 treated breasts. (The mean follow-up time was 36 months.) Of our Tl and T2 patients with clear resection margins that were boosted, there-was I local recurrence in 28 treated breasts. There was 1 local recurrence in the nonboosted group of 68 patients. Except for one patient, all patients with positive margins were boosted. There were 2 local recurrences in the 23 Tl and T2 breasts with positive margins that were boosted. Of the patients with uncertain margins who were not boosted, there was one local recurrence in 20 treated breasts, Of those with uncertain margins that were boosted, there were no local recurrences in 19 treated breasts. From our results, it would appear that a boost to the primary site is unnecessary if the margins of resection are negative (by either inking or if it is clearly stated in the pathology report). In those patients with uncertain margins, most were done in the years before margins were routinely inked, but generous excisional biopsies were usually done. In this latter group of patients, there also was no added benefit to boosting.