Chronic rhinosinusitis a very common disease characterized by inflammation of the mucosa of the paranasal sinuses. Nasal endoscopy and computed tomography (CT) scans are successfully used as diagnostic modalities of nose and paranasal sinus diseases. CT scan has been traditionally considered as the gold standard for diagnosing Chronic rhinosinusitis. But high cost, radiation exposure and high rates of false positivity are important drawbacks. However, nasal endoscopy as an OPD tool helps in early categorization of patients for further evaluation by imaging. This is a cost cutting as well as time saving option. To compare nasal endoscopy and CT scan with respect to prediction of intrasinus involvement.To evaluate the role of nasal endoscopy as an effective alternative to CT-scan in diagnosing chronic rhinosinusitis.82 clinically diagnosed cases of chronic rhinosinusitis underwent CT scan and were advised to undergo diagnostic endoscopy. Both the modalities were compared for the diagnosis of chronic rhinosinusitis with focus on anatomic variations and the pathological findings in the nose and paranasal sinuses, and their correlation, specificity, sensitivity, positive predictive value and negative predictive values were calculated. The association between diagnostic endoscopy and CT was calculated using χ 2 test. Pearson χ 2 value: 8.173, P value=0.004 (<0.05) i.e. significant. The sensitivity and specificity of nasal endoscopy was calculated with respect to diagnosing chronic rhinosinusitis in comparison to CT-scan. The results were: sensitivity was 78.08% (95% CI 66.57-86.58%), specificity was 66.67% (95% CI 30.91-90.95%) while the positive predictive value: 95% and the negative predictive value was 27.27%. CT scan is considered to be the gold standard for sinonasal imaging. Endoscopy can predict the intrasinus involvement in rhinosinusitis thereby reducing overdone CT-scans.