OBJECTIVE Common bile duct dilatation (CBDD) represents part of a wide spectrum of pancreaticobiliary disorders, with different etiopathogenic mechanisms. The objective of this study was to compile the cases treated in our service during the last five years. METHODS Four cases of CBDD (17 months to 10 years of age) are reported. All of them presented abdominal pain and bilious vomiting. One patient previously had pancreatitis. Cholestatic jaundice was associated in only one patient. The diagnosis was made by ultrasound, being confirmed by endoscopic retrograde cholangiopancreatography (ERCP) in three cases and by computed tomography scan (CT) in one case. RESULTS Three patients had a single fusiform dilation of the extrahepatic bile duct (type I cyst, Alonso Lej-Todani classification), which were treated by cyst excision and hepaticojejunostomy by using a Roux-en-Y limb. In one patient, the ERCP detected a combined dilatation of the intra- and extrahepatic bile duct (type IV cyst), associated with an anomalous choledochopancreticoductal junction with a distal obstruction of the common bile duct. In the case, the treatment consisted of a transduodenal esfintherotomy. CONCLUSIONS Based on our experience and a literature review, an increasing incidence of this pathology is deduce. Therefore, the relevance of ultrasounds and ERCP in the diagnosis and visualization of pancreatobiliary ducts and the choice of treatment, depending on the CBDD, are discussed.