Objectives: To evaluate performing endoscopic frontal sinusotomies in the setting of large supra agger frontal cells (SAFC or formerly known as Kuhn type 3 frontal cells) using the unzip technique during endoscopic sinus surgery. Methods: A review of prospectively collected data was performed of 32 consecutive patients (37 sides) who underwent endoscopic frontal sinusotomies for SAFCs between January 2012 and October 2016 to identify and evaluate subjects the unzip technique for removal of SAFCs was performed. Data collected and analyzed included demographics, CT imaging characteristics, findings at surgery, use of frontal sinus stents, preoperative and postoperative SNOT-22 quality of life scores, primary versus revision surgery, and size of intraoperative and postoperative frontal sinusotomy, and complications. The operative technique was described. Results: Eighteen (18) subjects (23 sides) underwent successful frontal sinusotomies and removal of SAFCs using the unzip technique. All sides had endoscopically confirmed persistent postoperative patency with a mean follow-up of __._ months. None of the patients required revision surgery. No cases of CSF leak, epistaxis requiring packing or cauterization, or orbital injury occurred. Conclusion: The unzip frontal sinusotomy technique for removal of Kuhn type 3 frontal cells provides safe and effective access to the native frontal sinus when the natural outflow tract can be identified. Key Words: Anatomy, frontal sinusitis, sinus surgery, endoscopic, frontal cell.