Introduction:Endoscopic retrograde cholangiopancreatography (ERCP) for asymptomatic common bile duct stones (CBDS) has been associated with an increased risk of post-ERCP pancreatitis (PEP). Patients with asymptomatic CBDS at the time of ERCP include those with incidentally discovered CBDS (group A) and previously symptomatic patients with CBDS who became asymptomatic after conservative treatment for symptomatic CBDS, including obstructive jaundice or acute cholangitis (group B). In this study, we aimed to examine PEP risk in group B by comparing PEP risks between groups A, B, and currently symptomatic patients (group C).Methods:In this multicenter retrospective study, we examined 77 patients in group A, 41 patients in group B, and 1225 patients in group C who had native papillae. PEP incidence rates between asymptomatic patients at the time of ERCP (groups A and B) and symptomatic patients (group C) were compared using one-to-one propensity score matching. Bonferroni’s correction analysis was also performed to compare PEP incidence rates among the three groups.Results:As per our findings, PEP incidence rate in propensity score-matched groups A and B was significantly higher than that of propensity score-matched group C (13.2% [15/114] versus 4.4% [5/114], respectively, P = 0.033). In groups A and B, PEP incidence rates were 11.7% (9/77) and 14.6% (6/41), respectively. PEP risk in group B was similar to that in group A (P = 1.0). PEP incidence in group B was significantly higher than PEP incidence in group C (14.6% (6/41)) vs. 2.9% (35/1225)) (P = 0.005)).Conclusions:ERCP for previously symptomatic patients with CBDS who became asymptomatic after conservative treatment for symptomatic CBDS may increase the risk of PEP compared with ERCP for currently symptomatic patients. Thus, ERCP should be performed before patients become asymptomatic using conservative treatments if patients can tolerate ERCP procedures.