The records of 21 consecutive patients referred for breast-conservation treatment of early-stage mammary carcinoma contained insufficient histopathologic documentation of adequate resection margins after tumor excision at other hospitals. All patients underwent postbiopsy mammography before reexcision of the tumor bed. In 12 of the 21 cases, there was pathologic evidence of macroscopic or microscopic residual tumor. In seven of the 12 cases, there was no clinical or mammographic evidence to suggest residual carcinoma. The findings indicate that mammography is insufficient to evaluate the completeness of tumor excision in the absence of histopathologic documentation.