Functional endoscopic sinus surgery (FESS) is one of the minimally invasive techniques which depends on nasendoscopes to expand the nasal drainage pathways of the paranasal sinuses and improve sinus ventilation and ease entrance of topical medications. Uncinectomy is the vital step in this procedure. Chronic rhinosinusitis that do not respond to medications is the main indication in treatment of inflammatory and infectious sinus diseases. To assess whether partial uncinectomy is fairly sufficient to improve patients symptoms, operative time and postoperative complications in the surgery of solitary maxillary sinusitis. In this prospective comparative study, 36 patients with localized maxillary sinusitis referred to surgery after medical treatment failure. They were divided into two equal groups; partial uncinectomy accomplished in group I while complete uncinectomy was done in group II. Partial uncinectomy had shorter operative time (statistically significant), less complications, and more effective in decreasing postoperative postnasal dripping over complete uncinectomy. On the other hand, complete uncinectomy was better in decreasing headache, nasal obstruction and anterior nasal discharge. Partial uncinectomy is more effective in decreasing complications and operative time. So it is the procedure of choice in patients with solitary maxillary sinusitis.