Background We evaluated the accuracy of nasal endoscopy in diagnosing chronic rhinosinusitis (CRS) compared with paranasal sinus computed tomography (CT). Methods Two authors independently searched the 5 databases (PubMed, SCOPUS, Embase, the Web of Science, and the Cochrane database) up to March 2019. For all included studies, we calculated correlation coefficients between the endoscopic and CT scores. We extracted data on true-positive and false-positive and true-negative and false-negative results. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool (version 2). Results We included 16 observational or retrospective studies. A high correlation ( r = .8543; 95% confidence interval [CI] [0.7685–0.9401], P < .0001, I2 = 76.58%) between endoscopy and CT in terms of the diagnostic accuracy for CRS was apparent. The odds ratio (Lund–Kennedy endoscopic score ≥1) was 7.915 (95% CI [4.435–14.124]; I2 = 28.361%). The area under the summary receiver operating characteristic curve was 0.765. The sensitivity and specificity were 0.726 (95% CI [0.584–0.834]) and 0.767 (95% CI [0.685–0.849]), respectively. However, high interstudy heterogeneity was evident given the different endoscopic score thresholds used (Lund–Kennedy endoscopic score ≥1 vs 2). In a subgroup analysis of studies using a Lund–Kennedy endoscopic score threshold ≥2, the area under the summary curve was 0.881, and the sensitivity and specificity were 0.874 (95% CI [0.783–0.930]) and 0.793 (95% CI [0.366–0.962]), respectively. Conclusion Nasal endoscopy is a useful diagnostic tool; the Lund–Kennedy score was comparable with that of CT.