Abstract : Radiologic assessment of the nose and paranasal sinuses is vital in identifying the site and extent of sinonasal disorders and in planning surgical treatments. To assess the frequency of the anatomical variations of the nose and paranasal sinuses in chronic rhinosinusitis and it's importance in patients undergoing functional endoscopic sinus surgery. This cross-sectional study consisted of 25 patients (17) males, (8) females who were attending Otorhinolaryngology Department at Al-Shaheed Ghazi Al-Hariri Hospital for Surgical Specialties / Medical City Teaching Complex, from October 2019 to December 2020. A detailed history, clinical examination, computerized tomographic imaging had been done and taken to see the detailed anatomy of the nose and paranasal sinuses and to evaluate the presence of anatomical variations and soft tissue abnormality. C.T scan of 25 patients, age from (19-70) years with chronic rhinosinusitis (CRS) has detected multiple types of anatomic variations with septal deviation being the most frequent in 15 patients (60%), concha bullosa was detected in 11 patients (44%), agger nasi cells in 10 patients (40%), bulla ethmoidalis in 4 patients (16%), onodi cells in 3 patients (12%), haller cells in 2 patients (8%), frontal cells type III and IV in 2 patients respectively (8%). Other anatomical variations like aerated septum, aerated uncinate process, Keros class II and III and hypoplastic frontal sinus also detected. Anatomical variations in the nose and paranasal sinuses are not unusual. Computed tomography is the gold standard method in radiological assessment of chronic rhinosinusitis and in pre-surgical evaluation in every patient undergoing functional endoscopic sinus surgery. Multiplanar scan is very important to assess the paranasal sinuses in three-dimensional way before surgery.