OBJECTIVES: The advent of endoscopic ultrasound (EUS) in the 1990s provided an alternative to endoscopic retrograde and magnetic resonance cholangiopancreatography (ERCP/MRCP) in the evaluation of the biliary tree. The aim of this study was to assess the value of selective EUS in the diagnosis of gallbladder and common bile duct (CBD) stone disease in patients with negative conventional imaging. METHODS: All patients undergoing biliary EUS between January 2000 and December 2004 were identified from the radiology computerised database. Forty-two patients (25 male, mean age 53 ± 3.2 years) with negative prior USS, CT and MRCP underwent EUS to evaluate for the presence of gallstones or microlithiasis. Prior and later radiological investigations, hospital readmission, and the need for further surgical intervention were also analysed. RESULTS: EUS was normal in 17 patients and demonstrated signs of recent acute pancreatitis in 8 patients. Cholelithiasis or microlithiasis was identified in 14 patients, and choledochal stones in 6 patients. In 1 patient, calculi were seen in the CBD but not the gallbladder. In a further case with recurrent acute pancreatitis, chronic pancreatitis was diagnosed on EUS. All patients with CBD stones underwent ERCP and sphincterotomy, and stones were universally confirmed. One patient with gallbladder calculi alone underwent cholecystectomy and the latter developed jaundice whilst awaiting cholecystectomy and underwent ERCP which demonstrated CBD microlithiasis. No patients with a normal EUS have subsequently been diagnosed with cholelithiasis. CONCLUSIONS: EUS provided additional diagnostic information in 16 of the 41 (39%) patients. Moreover, exclusion of gallstones/microlithiais is also important as it facilitates a search for other causes of pancreatitis. In conclusion, most cases of cholelithiasis can be diagnosed with standard imaging modalities but when these fail to identify a cause, EUS has an important role.