a b s t r a c tBackground: Although Middle East respiratory syndrome coronavirus (MERS-CoV) diagnostic delays remain a major challenge in health systems, the source of delays has not been recognized in the literature. The aim of this study is to quantify patient and health-system delays and to identify their associated factors. Methods: The study of 266 patients was based on public source data from the World Health Organization (WHO) (January 2, 2017-May 16, 2018). The diagnostic delays, patient delays, and health-system delays were calculated and modelled using a Poisson regression analysis. Results: In 266 MERS-CoV patients reported during the study period, the median diagnostic delays, patient delays, and health-system delays were 5 days (interquartile [IQR] range: 3-8 days), 4 days (IQR range: 2-7 days), and 2 days (IQR range: 1-2 days), respectively. Both patient delay (r = 0.894, P = 0.001) and health-system delay (r = 0.163, P = 0.025) were positively correlated with diagnostic delay. Older age was associated with longer health-system delay (adjusted relative ratios (aRR), 1.011; 95% confidence intervals (CI), 1.004-1.017). Diagnostic delay (aRR, 1.137; 95% CI, 1.006-1.285) and health-system delays (aRR, 1.217; 95% CI, 1.003-1.476) were significantly longer in patients who died. Conclusion: Delays in MERS-CoV diagnosis exist and may be attributable to patient delay and healthsystem delay as both were significantly correlated with longer diagnosis delay. Early MERS-CoV diagnosis may require more sensitive risk assessment tools to reduce avoidable delays, specifically those related to patients and health system.