Background/Aim. Mucocele of a paranasal sinus is a benign non-neoplastic condition characterized by cystic expansion and distension of the sinus cavity by retained mucoid secretions. Etiology is unknown. The purpose of this study was to estimate the efficiency of the endoscopic middle meatal antrostomy (MMA) as a treatment modality in patients with maxillary sinus mucoceles. Methods. This retrospective study involved 11 patients with maxillary sinus mucoceles/pyoceles treated endoscopically in the Clinic for Otorhinolaryngology of Military Medical Academy, Belgrade over a 3-year period (2005-2007). The presented symptoms and signs, radiological and pathohistological findings and surgical treatment were reviewed. Results. There were four females and seven males, age 22 to 65 years (mean 33 years). Two patients were with allergic rhinitis. All the patients complained of nasal obstruction, ten had facial pain, seven had nasal discharge, five had cheek pressure, and four had epiphora, and four had headaches. On endoscopic nasal examination, the medial wall of the maxillary sinus was bulging in ten patients. Purulent drainage was seen in eight patients, septal deviation in ten, and polyps were found in two of the patients. The MMA and marsupialization of the mucocele were performed in all the patients. On histopathological examination, the mucocele wall showed a lining composed of respiratory epithelium. Postoperative follow-up ranged between 8 and 44 months (in six patients, it ranged from 24 to 44 months). No patients required revision surgery. Conclusion. The MMA with mucocele marsupialization abolishes middle meatal obstruction and establishes better drainage and ventilation of the maxillary sinus and restitution of its mucosa.