Method : A prospective study in 141 patients with suspected CBD stones based on clinical, biochemical and imaging by trans-abdominal ultrasonography or computed abdominal tomography. All patients underwent EUS. All patients with high risk for CBD stone underwent ERCP after the EUS. For patients with intermediate risk for CBD stone, ERCP's were done at the discretion of the attending physicians. For patients with ERCP done, the diagnosis of CBD stone was confirmed by ERCP demonstration of CBD stone. In patients with intermediate risk without ERCP done, clinical follow up to assess biliary symptoms and liver function test as surrogated markers for CBD stone at 3 months interval for one year were done. The false negative rate in patients with EUS and ERCP done in this study was used to estimate the false negative rate in patients in clinical surrogated group.