Background: Coronavirus disease 2019, known as a widespread, aerosol spreading disease, has affected >549 000 000 people since 2019. During the lockdown period, dramatic reduction of elective endoscopic procedures, including endoscopic retrograde cholangiopancreatography, had been reported worldwide, leading to delayed diagnosis and treatment. Nevertheless, whether patients' hospital stays and complication rate of endoscopic retrograde cholangiopancreatography (ERCP) during the lockdown period were influenced by the pandemic still remains controversial. Methods: Patients who diagnosed with obstructive jaundice and acute cholangitis in the lockdown period, May 16 to July 26, 2021, were compared to the same prepandemic period in 2019. Results: A total of 204 patients in 2019 and 168 patients in 2021 were diagnosed with acute biliary cholangitis or obstructive jaundice, and 82 of the patients in 2019 and 77 patients in 2021 underwent ERCP (p = 0.274). Patients whose quick Sequential Organ Failure Assessment (qSOFA) score was ≥ 2 occurred more during the lockdown period than during the normal period (24/77, 31.1% vs 12/82, 14.6%; p = 0.013). The initial laboratory data, including, total bilirubin (4.12 in 2021 vs 3.08 mg/dL in 2019; p = 0.014), gamma-glutamyl transferase (378 in 2021 vs 261 U/L in 2019; p = 0.009), and alkaline phosphatase (254 in 2021 vs 174 U/L in 2019; p = 0.002) were higher during the lockdown period compared to 2019. Hospital stay was statistically significant longer in the lockdown period (11 days [7.00-22.00] in 2021 vs 8 days in 2019 [6.00-12.00]; p value = 0.02). Multivariate analysis showed that qSOFA ≥ 2 (hazard ratio [HR] = 3.837, 95% confidence interval [CI] = 1.471-10.003; p = 0.006), and malignant etiology (HR = 2.932, 95% CI = 1.271-6.765; p = 0.012) were the statistically significant factors for a prolonged hospital stay, which was defined as hospital stay >21 days. ERCP-related complications and mortality rate were not statistically different between the two periods. Conclusion: Patients from May 16 to July 26, 2021, the lockdown period, had longer hospital stays and higher biliary tract enzyme levels, which indicated more severe disease. Nevertheless, ERCP could be safely and successfully performed even during the medical level 3 alert lockdown period without causing an increase in procedure-related complications and mortality.