Ultrasonography is the primary modality to conform the presence of biliary obstructon. Obstructon in biliary tree may be extrahepatc or intrahepatc and bile duct obstructon may be due to variety of malignant and benign masses. The commonest cause of obstructng mass is cholangiocarcinoma. Malignant masses causing biliary obstructon has a wide spectrum of radiological appearances.Objectve of study was to identfy the magnitude of mass lesion causing biliary obstructon at hepatc hilar region and efectveness of ultrasonography in the diagnosis of the hilar obstructon. This study was undertaken in Bir Hospital. Retrospectve analysis of one year record was done of those cases admited for endoscopic retrograde cholangiopancreatography followed by abdominal ultrasonography.  Out of total 73 patents of obstructve biliary pathology, 21 (28.70%) of the patents diagnosed biliary obstructon due to mass lesion and among those 21 patents with mass lesion, the level of obstructon in hepatc hilum was reported in 52.40% (N=11). Abdominal USG is capable in diagnosing tumoral bile duct obstructon. For defnite diagnosis the direct fne needle aspiraton biopsy or bile sampling for cytology has to be done either by PTC or ERCP. Key words: Ultrasonography, obstructon, bile duct, cholangiography.