A technique for three-dimensional (3D) computed tomography (CT) of the paranasal sinuses was evaluated. The influence of milliamperage and reconstruction algorithms on image quality was studied in a phantom. Eleven patients with bony abnormalities of the paranasal sinuses underwent CT to assess the clinical impact of 3D CT protocol. Contiguous 1.5-mm sections obtained at 120 kVp/175 mA/1.9 sec can provide 3D images with high diagnostic image quality. This technique offers the advantage of a much lower dose than that of the conventional CT (CCT) examination of paranasal sinuses. Three-dimensional CT protocol of paranasal sinuses is suggested for use for the evaluation of bony abnormalities and for preoperative planning of the above region.