Use of anatomic permanent expandable implant after skin-sparing mastectomy (SSM) permits a 1-stage immediate breast reconstruction with an optimum breast shape. Preservation of most of the mammary skin after SSM on 1 side and anatomic prosthesis shape on the other makes breast reconstruction easier and enhances the quality of the esthetic results. The authors describe their experience with 40 immediate breast reconstructions after SSM performed over a period of 2 years explaining some technical details. The implant is placed in a submuscular pocket, or preferably, depending upon the condition of the muscles and skin flaps after mastectomy, in a submuscular-subfascial pocket. In this case, the undermining of the pocket is submuscular in its upper part under the major pectoralis muscle and subfascial in the lower part of the breast undermining the adipo-fascial tissues above the anterior serratus muscle. The submuscular dissection is done in continuity with the subfascial dissection to allow the complete closure of the soft tissues over the implant. In this case, the minor consistency of subfascial tissues compared with muscle in the inferior pole of the breast allows the easier and quicker distention of the soft tissue overlying the prosthesis during the inflation phase and ensures a good shape of the breast soon after surgery. Whenever possible, the mastectomy is performed through a periareolar skin incision that is closed with a purse-string suture. Finally, the authors discuss the indications of 2 different-shaped anatomic permanent expandable implants: full-height and short-height prostheses with different shape and fullness of the upper pole of the implant.