Background/aims: To evaluate the accuracy of magnetic resonance cholangiography for detection of bile duct calculi and stenosis. Methods: Half-Fourier single-shot rapid acquisition with relaxation enhancement sequence magnetic resonance cholangiography was performed prospectively in 68 patients who were suspected of having choledocholithiasis or biliary tree stenosis. On the basis of findings at ultrasound, computed tomography, endoscopic retrograde or percutaneous cholangiography, intraoperative cholangiography or choledocoscopy and exploration, final diagnoses were normal bile ducts (n=8), choledocholithiasis (n=28), benign or malignant stenosis (n=32). Results: Choledocholithiasis was diagnosed with a sensitivity of 96% and a specificity of 98%. False negative readings occurred due to stones less than two mm at in size at the distal common bile duct. A false diagnosis of choledocholithiasis (single impacted stone) by magnetic resonance cholangiograph occurred in only one case for whom the final diagnosis was main bile duct adenocarcinoma, suspected on endoscopic retrograde cholangiography and confirmed at surgery. Bile duct stenosis was diagnosed with a sensitivity of 97% and a specificity of 94%. Conclusions: With magnetic resonance cholangiography, bile duct calculi and stenosis can be diagnosed with high accuracy. It is a fast, accurate and noninvasive alternative to endoscopic retrograde cholangiography in the evaluation of biliary tract disease.