Recent advances in the pathophysiology of the nasal cavity and paranasal sinuses and the development of endoscopic equipment and techniques have led to a new "functional" surgical management of chronic or recurrent sinusal conditions. The ostiomeatal complex is a narrow and intricate passage way providing aeration and mucus clearance from anterior ethmoid sinus, maxillary sinus and frontal sinus. CT, allowing the detailed demonstration of normal and abnormal patterns of the ostiomeatal complex, permits accurate preoperative planning, which has reduced the number of surgical complications. Ostiomeatal complex anatomy and the corresponding CT features are analyzed, as seen in 85 patients with or without rhinosinusal inflammatory lesions. The CT technique with coronal and axial scans and electronic parasagittal reconstructions, is also reported. Finally, the images obtained on different CT planes are compared, as proposed by other authors.