The use of the transaxillary incision has enabled augmentation mammoplasty with a scarless breast. However, the classic technique has been associated with high rates of asymmetry, malposition, and high riding implants. With the addition of endoscopic assistance, retropectoral pocket visualization and better control of the lower pole has been facilitated. Nevertheless, pitfalls in patient selection and technique abound. In this study, the authors experience with endoscopic transaxillary breast augmentation is reviewed, with particular attention to both the anatomic characteristics associated with favorable and unfavorable outcomes and technical nuances that have improved aesthetic results. One hundred and ninety-seven endoscopic transaxillary breast augmentations were performed during this study. All patients underwent augmentation with saline implants, with a mean volume of 298 mL. Preoperative pseudoptosis or grade I ptosis was present in 14 patients, and 4 patients had mild or moderate tuberous deformity. Thirty-four patients had short lower pole anatomy, with areola-to-inframammary crease length of < or =3.5 cm. There were 19 patients identified with pectoralis major hypertrophy resulting from strength training. One patient (0.5%) required conversion to an open technique for control of bleeding. Three patients (1.5%) required intraoperative conversion to an open technique for inadequate implant position and breast shape (2 with tuberous deformities and 1 with ptosis). Seven patients (3.5%) underwent revision for malposition (5 superior and 2 inferior). There were no infections, seromas, postoperative hematomas, or significant encapsulations. Patient selection is of paramount importance in minimizing complications and optimizing the results of endoscopic-assisted transaxillary breast augmentation. Patients with deficient lower breast poles, sharply defined inframammary creases with short areola-to-fold distances, pectoralis major muscular hypertrophy, ptosis or pseudoptosis, and any form of tuberous breast deformity should be identified carefully and considered judiciously. Technical refinements that maximize safety and improve the aesthetic results with endoscopic-assisted transaxillary breast augmentation are described.