Cosmetic results from radiation following breast-conserving surgery and radiation therapy are generally poorer in women with large or heavy breasts. Breast reduction carried out at the time of definitive surgery allows this group of women to undergo breast-conserving surgery and radiation with excellent cosmetic results. Four cases are presented in which partial mastectomy was carried out in conjunction with immediate bilateral breast reduction. All patients had clear margins and all had excellent cosmetic results following radiation therapy. Immediate breast reduction should be considered in women with large or heavy breasts who otherwise qualify for breast-conserving surgery.