Abstract: The paper presents an analysis of the data of ultrasound, CT, MRCP and intraoperative cholangiography in patients with bile duct cyst. Echographic data are presented in 86 patients, CT in 61, MRCP in 8 and intraoperative cholangiography in 73 patients with this pathology. Ultrasound is a highly sensitive and informative screening method for the diagnosis of choledochal cysts in children. To increase the specificity of ultrasound with cysts of the common bile duct, a dynamic study of the contractility of the biliary system after taking a "choleretic breakfast" is proposed. Currently, in the diagnosis of pathology of the biliary tract, CT of the abdominal cavity and MRCP are effective noninvasive methods, alternative to invasive ERCP. It has been established that the final verification of the form of bile duct cysts, abnormal fusion of the pancreatic duct into the cyst cavity is determined using MRCP and intraoperative cholangiography, which allows you to choose the optimal method of surgical treatment.