Pneumosinus dilatans is defined as an abnormal enlargement of paranasal sinuses containing only air. The frontal sinus is most commonly affected, but the maxillary sinus is rare. The surgical aims of pneumosinus dilatans are to re-establish a permanent pressure equilibrium in the involved sinus and to correct possible facial deformity. Generally, pneumosinus dilatans of maxillay sinus is corrected by ostectomy of anterior wall of maxillary sinus and repositioning of removed bony fragment. Despite correction of anterior facial contour asymmetry, asymmetry of facial width remains to be a problem. Therefore, the authors present a technique for correction of pneumosinus dilatans of maxillary sinus by segmental zygoma ostectomy and maxilloplasty. A 16-year-old girl with a slowly enlarging mass in the right side of the face was referred to our department. No history of sinusitis, nasal obstruction or facial trauma were noted. CT scan presented an abnormal enlargement of right maxillary sinus. Surgery was delayed for 2 years until maturation of facial bone. Surgical correction was accomplished through circumferential osteotomy with repositioning of maxillary segment and segmental zygoma ostectomy. Postoperatively, the patient's facial contour was improved with equal malar height and width and no significant complication was noted.