Mastopexy and reduction mammaplasty reshape breast parenchyma and restore youthful contour in women with ptotic breasts. However, recurrent ptosis and breast base widening are common. We have been using internal autologous or cadaveric (AlloDerm) dermal slings to circumferentially support and shape the breasts for symmetry or rejuvenation. Ten patients underwent unilateral mastopexy (3), unilateral reduction-mastopexy (1), bilateral mastopexy (5), or bilateral reduction-mastopexy (1) with an internal dermal sling to correct breast reconstruction asymmetry (2), congenital asymmetry (2), or acquired ptosis (6). Three of 6 patients acquired breast ptosis after massive weight loss. Autologous dermis was used in 5 patients, and 5 patients were reconstructed with AlloDerm. Patients have maintained projection and breast base width after 6 months to 3 years. In conclusion, internal dermal slings improve shape, breast projection, and base width in select patients undergoing mastopexy. An algorithm based on quantity and quality of native skin is provided.