Size of tumor has not been established as a predictor of tumor recurrence in the breast following conservative surgery and radiation therapy. We analyzed 783 patients with infiltrating carcinoma treated with simple excision and radiation therapy. Median follow-up was 91 months. Median age at diagnosis was 50 years. There was a 13% recurrence among patients with T1 lesions compared with a 12% recurrence among patients with T2 tumors. Size did not predict for local recurrence when the tumor was analyzed by 1-cm increments and whether the tumor was estrogen receptor protein positive or estrogen receptor protein negative. Patients with an extensive intraductal component had a significantly higher local recurrence rate for every tumor size compared with patients with extensive intraductal component-negative tumors. We concluded that size did not predict local recurrence.