Prosthetic reconstruction remains the most common technique for breast reconstruction after mastectomy. Subpectoral device placement has been criticized for inadequate control of the lower pole. One innovation has been the insertion of Alloderm along the inferior border of the pectoralis major muscle. This provides a secure attachment of that muscle inferolaterally without the need for total sub-muscular pocket dissection. The Alloderm graft creates a secure pocket, defines the inframammary fold, and provides an additional layer of coverage for the device. After completion of expansion, expanders were exchanged to permanent implants. The final reconstructive result was assessed by patients and surgeons using a standardized instrument. We assessed time to complete reconstruction, complication rates, patient satisfaction, and cosmetic outcome. 58 breasts in 43 women were reconstructed with tissue expanders and Alloderm. 41 breasts in 30 women completed exchange to implants. Mean time to complete reconstruction was 199 days. Complications after expander and Alloderm placement included mastectomy flap necrosis(5.2%), cellulitis(5.2%), seroma(3.4%), and explantation(1.7%). There were no complications after exchange to implants. Alloderm appears to be a useful adjunct in immediate prosthetic breast reconstruction. Use of Alloderm has a low complication rate, helps create an aesthetically pleasing breast, and affords an expeditious reconstruction.