Forequarter (interscapulothoracic) amputation is a major ablative surgical procedure that was originally described to manage traumatic injuries of the upper extremity. Currently, it is most commonly used in the treatment of malignant tumours of the arm. With the advent of limb-sparing techniques, primary forequarter amputation is performed less frequently, but remains a powerful surgical option in managing malignant tumours of the upper extremity; therefore, surgeons should be familiar with this procedure. A classic case report of forequarter amputation, with emphasis on indications and surgical techniques, is presented.