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Introduction Asymptomatic common bile duct (CBD) dilatation is increasingly identified on cross-sectional imaging performed for unrelated indications. Current BSG guidelines recommends endoscopic ultrasound (EUS) for the investigation of suspected biliary obstruction, particularly in the presence of abnormal liver biochemistry or biliary symptoms. However, the diagnostic value of EUS in patients with isolated, asymptomatic CBD dilatation and normal liver transaminases remains uncertain.Methods We conducted a retrospective analysis of all EUS procedures performed at a single UK centre between January 2023 and December 2025. Of 850 patients screened, 44 met the inclusion criteria. Patients were included if EUS was undertaken for incidentally detected CBD dilatation on CT, MRCP or ultrasound, in the absence of biliary symptoms and with normal liver transaminases. Patients with jaundice, abdominal pain, pancreatitis,known gallstones or CBD stones, abnormal liver biochemistry, or alternative primary indications were excluded. A positive EUS was defined as a clinically relevant finding explaining CBD dilatation.Results Forty-four patients were included (median age 66 years; 87% female). Isolated CBD dilatation was the most common indication (78%), while 22% had a double duct sign on imaging. Fourteen patients (32%) had previously undergone cholecystectomy. EUS was normal with no significant pathology identified in 38 patients (86%). Incidental benign abnormalities were detected in six patients (14%), including CBD polyps (n=2), benign pancreatic cysts (n=2), and simple liver cysts (n=2). No pancreaticobiliary malignancies were identified, and no patient required EUS-guided therapeutic intervention or experienced a subsequent change in clinical management.Conclusion In patients with incidentally detected CBD dilatation on scan and normal liver transaminases, EUS demonstrates a very low diagnostic yield, with no malignant pathology identified in this cohort of patients. These findings support a selective, guideline-aligned approach to EUS referral, reserving investigation for patients with abnormal liver biochemistry or biliary symptoms. More selective use of EUS in this low-risk subgroup may reduce unnecessary invasive investigations and improve endoscopy resource utilisation.