Drawbacks to conventional Le Fort III osteotomy include bleeding, infection, relapse, and scar at the coronal incision. We performed an endoscopically assisted Le Fort III osteotomy with an ultrasonic scalpel in cadavers to develop a new technique that minimizes such complications. Endoscopically assisted Le Fort III osteotomy was performed in 3 fresh, adult human cadavers. Access incisions included the transconjunctival lower lid with lateral canthotomy, the lateral upper gingivobuccal sulcus, and a stab incision in the medial aspect of the upper eyelid. Osteotomies at the zygomaticofrontal suture, the lateral orbital wall, the orbital floor, and the medial orbital wall were carried out with an ultrasonic scalpel under direct and endoscopic visualization from the trasconjunctival incision. The zygomatic arch and the pterygomaxillary region were osteotomized via the upper gingivobuccal sulcus incisions. The nasofrontal junction and the septum were accessed and cut via a stab incision in the medial upper eyelids. Disimpaction was completed with minor digital pressure inferiorly.Each of the 3 Le Fort III osteotomies was complete, and mobility was checked by manual examination. There was a steep learning curve to the operation, but the final cadaver dissection took 99 minutes to complete. The ultrasonic scalpel provided for maximal ease in cutting bone and minimal disruption to adjacent soft tissues as judged by postoperative direct examination. This cadaver study demonstrates the feasibility of a minimally invasive, endoscopically assisted Le Fort III osteotomy using an ultrasonic scalpel. Further experimental work combined with refinements in technique and equipment will help bring this advancement into clinical application.