Purpose: Three-dimensional(3D) magnetic resonance(MR) projection imaging was evaluated as a noninvasive alternative to direct cholangiography for the assessment of its reliability in patients with obsructive jaunoiceMaterials and Methods: A heavily 72-weighted gradient-echo sequence(PSIF) was used for 3D MR projecion imaging of the biliary system in five healthy volunteers and 25 patients with obstructive jaundice. The3D images of the bile ducts were formed by stacking consecutive coronal MR images obtained with a fast imaging method to a maximum-intensity protection algorithm.Results : In the volunteers, MR cholangiography could demonstrate the anatomy of the biliary tract in only two subjects. The extrahepatic and intraheparic bile ducts were well visualized in 23 patients with obstructive jaundice. The love of obstruction and the grade of dilatation were dipicted with MR cholanglography in all cases. And the cause of obstruction could be determined with MR cholangiography in 18 cases, MR cholangiography was successful in two patients in whom ERCP failed. The gallbladder or dilated pancreatic duct not demonstrated by means of direct cholangiography was demonstrated with MR cholangiography in six cases.Conclusion : MR cholangiography may be a useful adjunctive tool for the noninvasive evaluation of patients with obstructive Jaundice.