Background: biliary obstruction or cholestasis is a common medical or surgical problem. Broadly speaking, the causes can be divided into intrahepatic and extrahepatic. The diagnosis of biliary tree can be done by different imaging modalities starting from transabdominal ultrasonography, to magnetic resonance cholangeopancreatograpy (MRCP) to endoscopic ultrasonography (EUS) and endoscopic cholangeopancreatography (ERCP) for diagnosis and treatment. Aim of the present work: this study aimed to evaluate the accuracy of these different modalities when compared to ERCP as diagnostic methods for diagnosis of different biliary tree abnormalities. Patients and methods: eighty-four patients with obstructive jaundice were included and categorized into two groups group I: 56 patients with calcular obstructive jaundice, group II: 28 patients with non-calcular obstruction. Patients underwent history taking, clinical examination and routine laboratory investigations as well as tumor markers. Patients were examined by US, MRCP, EUS, ERCP and the findings of each modality were compared to ERCP. Results: the sensitivity and specificity of US in diagnosis of intrahepatic biliary dilatation (IHBRD) and common bile duct (CBD) dilatation were 81% , 100% and 33% and 100% for diagnosis of pancreatic tumors respectively. The sensitivity and specificity of MRCP in diagnosis of IHBRD was 97% and 100% successively and for CBD dilatation 79% and 100% successively and for diagnosis of pancreatic tumors 100% and 96% successively. The sensitivity and specificity of EUS in diagnosis of IHBRD were 100% and 100% successively and for CBD dilatation were 100% and 100% successively but in diagnosis of pancreatic tumors were 100% and 94% successively. Conclusion: Both MRCP and EUS were good diagnostic modalities for biliary obstruction and pancreatic tumors with sensitivity and specificity of >90% when compared to ERCP.