Mammography is the only examination capable of depicting malignant calcifications in breast. In some instances calcifications evident in mammogram and specimen mammograms are not observed in the histologic specimen. Therefore, wer retrospectively analyzed 27 cases in which hook-guided wire localization and biopsy had been performed to determine if microcalcifications were lost during histopathologic precessing. Calcium was apparently lost during preparation of the block in about 7% of the cases and after slide preparation in about 11%, for a total possible loss of 18%. The authors recommend a protocol for avoiding these loss that involves performance of a more comprehensive examination of histologic sections by the pathologist and radiographic reexamination of paraffinembedded tissue blocks with subsequent step sectioning by the pathologist.