Inadequate chest-wall skin following mastectomy for carcinoma continues to be a problem in many breast reconstructions. To avoid extensive surgery, serial tissue expansion has been advocated. Since 1977, one of the authors has used a simple method of tissue expansion that we have termed "modified tissue expansion", defined as the creation of an adequate breast mound in one or two stages using a permanent prosthesis. Ninety percent of patients undergoing breast reconstruction between 1978 and 1983 were reconstructed using this method. A retrospective analysis of these 208 patients is presented. There were no mortalities, and only a 6.3 percent complication rate. Skin necroses related directly to the prosthesis occurred once, and there were no prosthetic deflations. Eighteen percent had first-step reconstruction only. The initial prosthesis averaged 400 cc in size. Selected Halsted radical mastectomy and postradiotherapy patients were successfully reconstructed. Seventy-eight percent felt their results were excellent at 1 year. Two percent were dissatisfied. Multiple office visits and the potential problems of serial expansion were avoided. Modified tissue expansion is a simple and viable method and should be considered among the options for breast reconstruction following mastectomy.