A new problem has arisen for surgeons now that the pectoralis major muscle is routinely left in place after mastectomy. When the pathologist reports a tumor close to the fascial margin, there has been uncertainty regarding the significance of this finding. In the present study, the histories of 346 women with negative nodes who underwent modified radical mastectomy and had an uninvolved plane under the breast were reviewed. The distance from tumor to fascia was recorded by the pathologist, and the patients were divided into "Close" and "Not Close" groups. The "Close" group (90 patients) had tumors within one low power field (4 millimeters) of the fascia while the "Not Close" group (256 patients) had tumors more than 4 millimeters from the fascial margin. Twelve of the patients had local recurrence within an average follow-up period of 47 months, and a variety of analyses failed to show a statistically significant difference in local recurrence rates between the two groups. The results of this study indicate that tumor to fascia margin, as recorded by the pathologist, is not a strong determinant of local recurrence provided the areolar plane between the breast and the underlying fascia appears uninvolved at the time of mastectomy.