Expansile inflammatory diseases of the frontal sinuses may produce erosion of the posterior table of the frontal sinus. In these instances, the bone between sinus mucosa and intracranial dura is absent. Over the past decade, endoscopic frontal sinusotomy has emerged as the preferred technique for the treatment of refractory chronic frontal sinusitis. Endoscopic approaches also have a role in the most advanced instances of frontal sinusitis. A retrospective chart review of patients who were treated for frontal sinusitis with erosion of the frontal sinus posterior table was performed. Eight patients were identified. All patients underwent endoscopic frontal sinusotomy; some patients required multiple endoscopic procedures. Complete frontal recess dissection with identification of the frontal ostium was achieved for all involved frontal sinuses. In all cases, this postoperative result was monitored by CT scans (where indicated) and serial nasal endoscopy, which demonstrated good frontal sinus aeration and normal mucociliary clearance. Antibiotics were administered for culture-documented bacterial exacerbations, and systemic steroids were given for management of allergic fungal sinusitis and sinonasal polyposis associated with asthma. No patient underwent frontal sinus obliteration or cranialization. No suppurative intracranial complications were noted during the postoperative period. Endoscopic frontal sinusotomy can be used safely for the definitive management of frontal sinusitis associated with posterior table erosion. In fact, endoscopic techniques may represent the preferred approach for the treatment of this problem. Such an approach avoids the morbidity of more destructive alternatives (such as obliteration), and serves to create a frontal sinus with normal mucociliary clearance.