Women presenting with anterior thoracic depression, breast hypoplasia, and subsequent asymmetry are often diagnosed with Poland syndrome regardless of pectoralis involvement, or are placed in the generic category of breast asymmetry or skeletal dysplasias. Recently, though, the term "sunken chest" has been used to describe forms of chest wall depression that previously may have fallen under generic skeletal dysplasias. The authors believe that, combined with hypoplasia of the ipsilateral breast, superior location of the nipple-areola complex compared with the contralateral side, and normal pectoralis muscles, this represents a previously undefined and real condition called anterior thoracic hypoplasia. During the past 4 years, the authors have treated eight women who have presented with a diagnosis of Poland syndrome or pectus excavatum, all of whom share the same characteristics-unilateral sunken anterior chest wall, hypoplasia of the breast, superiorly placed nipple-areola complex, normal pectoralis muscle, and normal sternal position. All of the patients underwent correction of breast asymmetry and unilateral anterior thoracic hypoplasia with augmentation mammaplasty, a method that when tailored for each side yields good aesthetic results. The average age of the patients was 31 years and the average chest size was 34. Cup size, as measured by the patient's standard bra, was a B on the nonaffected side in all patients and an A on the affected side in all patients except one. Of the eight patients, seven had the right anterior chest and breast involved, whereas one patient had involvement on the left. For all of the patients, the nipple and areola of the hypoplastic side were smaller and in a more superior position compared with the contralateral side on visual inspection. In the eight patients, a total of 19 augmentations (15 primary augmentations and four revisions) and one mastopexy were performed. Ten inframammary-fold approaches and nine periareolar approaches were used, and all of the implants were placed in a partial submuscular position, except for two implants placed in a subglandular position that were converted to partial submuscular positions in a secondary setting. In all the women, the sternal head of the pectoralis muscle was present and the pectoralis muscle appeared to be equal in size compared to the contralateral side. Nine different types of implants were used. Average implant fill volume measured 412 cc on the hypoplastic side and 257 cc on the contralateral side. In follow-up, all of the patients were satisfied with their operation and rated their aesthetic outcome as very good to excellent. The authors believe that anterior thoracic hypoplasia is a real, previously misdiagnosed and undescribed condition, and that both chest wall and breast deformities can be corrected safely and with excellent results using proper augmentation planning and implant selection.