Fifty patients undergoing immediate reconstruction of the breast following modified radical mastectomy for carcinoma were characterized by their clinical findings and the pathologic features of their tumors. Evidence of nipple--areolar involvement by tumor was noted in five patients. This high incidence mitigates against nipple--areolar transplantation. In ten patients the breast contained multifocal tumor or intraductal carcinoma away from the primary tumor, thus emphasizing the importance of careful evaluation of the total tissue specimens. Four patients have had recurrence of tumor. The detection of the recurrence was not hindered by the presence of the prosthesis. In these four patients immediate reconstruction of the breast did not appear to adversely affect the natural history of the breast cancer. We suggest that when appropriate and thorough surgical extirpation followed by reconstruction is undertaken as a team effort among the general and plastic surgeons, pathologist and clinical psychologist, the optimal clinical and cosmetic results may be achieved. However, conclusive statements regarding the long-term implications of immediate reconstruction awaits additional follow-up.