Background: In patients with chronically diseased maxillary sinuses, poor mucociliary clearance may result from long-standing inflammation or scarring from previous surgery. This subset of patients often has persistent sinus disease despite medical therapy and adequate antrostomy. Endoscopic maxillary mega-antrostomy (EMMA) is a mucosal sparing technique that facilitates mucus clearance and sinus irrigation in terminally dysfunctional maxillary sinuses. EMMA involves extending the antrostomy through the posterior half of the inferior turbinate down to the floor of the nose, creating a significantly enlarged antrostomy. This study describes our results of EMMA in recalcitrant maxillary sinusitis. Methods: A retrospective review was performed of patients who underwent EMMA for recalcitrant maxillary sinusitis between July 2005 and September 2007. We studied diagnoses, comorbid factors, clinical efficacy, revision rate, and complications. Results: Twenty-eight patients (average age, 48 years) underwent 42 EMMAs for recalcitrant maxillary sinusitis. Average follow-up was 11 months. All patients had previous maxillary sinus surgery (mean = 2.3). Relevant comorbid factors included prior Caldwell-Luc or maxillofacial surgery (16/42), cystic fibrosis (11/42), asthma (11/42), and IgG deficiency (3/42). The most common symptoms reported were facial pain/pressure and purulent rhinorrhea. At the time of the most recent postoperative examination, 74% of patients reported complete resolution of symptoms while 26% reported partial symptomatic improvement. There were no complications and the revision rate was 0%. Conclusion: Maxillary sinuses that appear to be terminally diseased may be rehabilitated surgically without the need for surgical stripping. EMMA is an effective and safe treatment option for the management of recalcitrant maxillary sinus disease.