Background Total mastectomy without reconstruction is a commonly adopted procedure for managing breast cancer. Formation of lateral dog ears is very common, especially with large breast cup size. In this study, we assessed the feasibility of adding quilting sutures to the Y plasty technique to achieve more acceptable results in the avoidance of lateral dog ears in comparison to using Y plasty alone. Methods The study included 150 female patients with large breast cup size. Patients were randomized 2 : 1 between group A and group B. In group A, 3–5 quilting sutures were added to the lateral flaps of Y plasty. In group B, Y plasty only was adopted without the quilting sutures. Patients were followed up at 4-month intervals for at least 1 year. One year after surgery, patients filled in a questionnaire inquiring about the degree of discomfort in the area beneath the arm. Also, a plastic surgeon was asked to give a score about the cosmetic outcome of managing lateral dog ears both at 3 weeks and 12 months after surgery. Results Both groups were comparable in regard to age, BMI, breast cup size, and postoperative radiotherapy exposure. Patients in group A had better scores for satisfaction with the shape of the scar and comfort with the bra. Also, the blinded cosmetic outcome assessment was in favor of group A. Conclusion Adding quilting sutures to the lateral flap of the V-Y plasty technique is associated with a better cosmetic outcome in the management of lateral dog ears in mastectomy patients with large breast cup size.