The surgical treatment of chronic inflammatory frontal sinus disease over the past century has varied between intranasal and external procedures. There has been constant modification of these techniques; however, a single approach that will lead to relief of symptoms, eradication of disease with preservation of function, and a minimum of deformity has not yet been attained. The functional theory of sinus disease, the evolution of endoscopic techniques, and data provided by the computed tomography scan have renewed our interest in the anatomy of the lateral nasal wall and endonasal surgery. Extensive literature exists concerning the results of ethmoid, maxillary, and sphenoid endoscopic surgery. However, detailed information is not available on the treatment of inflammatory frontal sinusitis. The author presents the results of a retrospective analysis of a series of 101 patients with inflammatory frontal sinusitis who underwent endoscopic surgery that included the frontoethmoid complex. Results for improvement of symptoms as well as endoscopic findings are presented. Relief of symptoms was significant but did not correlate with postoperative endoscopic findings in patients with hyperplastic and polypoid sinusitis. Patients with anterior ethmoid cell encroachment on the frontal sinus outflow tract had a positive correlation between improvement of symptoms and postoperative endoscopic findings. Frontal recess stenosis was associated with a poor outcome. Anatomic obstruction of the frontonasal duct is most consistent with the functional theory of sinusitis.