Background: Magnetic resonance cholangiopancreatography is a relatively noninvasive technique of biliary and pancreatic duct imaging. MRCP technique utilizes T2-weighted sequences, in which bile is characterized by high signal intensity, whilst signal intensity of surrounding tissues is reduced. The purpose of this publication was to assess the diagnostic value of magnetic resonance cholangiopancreatography in the diagnostics of biliary dilatation. Material and Methods: MRCP examinations of 148 patients (48 men and 100 women; the average age was 56) performed on a 1.5T Achieva Philips device in the Provincial Hospital in Rzeszow between November 2011 and April 2013 were included in retrospective analysis. Examined group was divided into three subgroups: patients after cholecystectomy, patients with cholecystolithiasis and patients without gallbladder concretions. The definitive cause of biliary dilatation was determined mainly on the basis of MRCP and ECPW examinations, and, in individual cases, during intraoperative cholangiography and laparatomy. Results: Signal loss corresponding to probable concretions was identified in 34 cases. In the group of patients with cholecystolithiasis the cause of biliary dilatation was usually (45%) cholelithiasis. MRCP image was typical in 4 out of 9 malignant cases. The cause of biliary dilatation was usually (20%) a neoplasm in the group of patients without gallstones. Benign causes of biliary dilatation, apart from cholelithiasis, were identified in 16 individuals, including 4 cases in which the diagnosis was identified using MRCP, whereas in the remaining 12 cases ECPW examination proved conclusive to the final diagnosis. Conclusions: Magnetic resonance cholangiopancreatography enables reliable diagnosis of causes of biliary dilatation as long as they involve presence of gallbladder deposits and tumors. In benign causes of biliary dilatation, apart from cholelithiasis, MRCP picture is often atypical and therefore, the final identification of the cause of biliary dilatation is possible when this imagining method is combined with ERCP and additional tests.