Elliptical skin-sparing mastectomy in patients with large or ptotic breasts usually leaves loose mastectomy skin flaps, which need to be either resected or gathered over the DIEP flap. This results in poor control of the breast footprint and under-projected DIEP flaps in a loose mastectomy skin pocket, that tend to slip laterally towards the axilla. We believe that the use of a Wise pattern mastectomy will allow for immediate treatment of these concerns. A retrospective, uncontrolled analysis of a prospectively-maintained database of patients operated by the five surgeons performing breast reconstructions at the University of Montreal Hospital Centre. Study population was patients with a BMI of over 25 and grade II/III breast ptosis who underwent a Wise pattern mastectomy with immediate DIEP flap reconstruction. Analysis was performed of the complication rates of the technique in the first six months after the surgery. Out of a total of 53 breasts in 44 patients reconstructed with a DIEP flap immediately post Wise pattern mastectomy, we report nine cases of partial mastectomy-flap necrosis not needing revision, five cases of significant mastectomy flap necrosis needing debridement and skin grafting, and two cases of inability to adequately close the Wise pattern intraoperatively after DIEP placement, necessitating retention of DIEP skin in the inferior pole. None of the mastectomy flap complications occurred in irradiated breasts. In patients with large or ptotic breasts, the Wise pattern mastectomy before an immediate DIEP reconstruction allows for immediate shaping of the breast by controlling the breast pocket, footprint, and excess skin.