Introduction: Chronic Rhinosinusitis is a heterogenous entity with a number of contributing factors. Anatomical Variations of paranasal sinuses are one of them. CT-scan paranasal Sinuses can be a useful tool in the study of these variations and also in providing a roadmap for endoscopic sinus surgery. Current research aimed to study the anatomical variations in sinonasal area by CT scan paranasal sinuses and to correlate these anatomical variations with chronic rhinosinusitis (CRS). Material and Methods: In this study, 94 patients of CRS, who were refractory to medical treatment for more than 3 months, underwent CT scan paranasal sinus axial and coronal view with axial and coronal views, prior to functional endoscopic sinus surgery. All their information related to clinical findings, investigations was recorded in data sheets and was kept confidential. Scoring of sinus disease was done by Lund & Mackay Scoring System. Results: The most common anatomical variations were Deviated nasal septum (64.89%), concha bullosa (29.74%) and agger nasi cells (13.83%). Maxillary Sinus was the most commonly involved sinus (40.4%). Conclusion: After evaluation of the results obtained, we postulate that anatomical variations may increase the risk of mucosal disease of paranasal sinuses. We therefore, emphasize that CT scan paranasal sinus in patients with persistent symptoms of CRS for diagnosis and preoperative evaluation can be considered as an important investigation where appropriate to aid the clinical and endoscopic examination findings. This will help to facilitate safe and effective endoscopic sinus surgery.