The acute pancreatitis occurs in children much less often than in adults. Though, it usually has a sudden onset and, at the beginning, it proceeds with intensified pain in the area of the abdomen, thanks to the proper diagnostics and treatment, it seldom leads to permanent damage of the pancreas. The most common causes of pancreatitis, apart from calculosis of the gallbladder and other pathological conditions of bile ducts, are the injuries of the abdomen as well as various infectious factors. Acute biliary pancreatitis in children occurs rather seldom, since calculosis of the biliary ducts is not often observed at this age group. Cholesterolic calculosis of the biliary ducts in children most often concerns obese, adolescent girls. Gall stones, usually, consist of a mixture of cholesterol, bile pigments, calcium as well as inorganic substances. A case of a 15.5‑year‑old girl who was hospitalised in our Clinic is presented below. The girl suffered from the pain in the abdomen. On admission, she was initially diagnosed the acute pancreatitis. The results of the laboratory tests (higher activity of amylase in serum and urine, higher activity of lipase, and increased concentration of transaminase) and the ultrasonography of the abdomen let the doctors definitively diagnose the acute biliary pancreatitis. A strict diet, intravenous irrigation, proton‑pomp inhibitors, administration of painkillers and antibiotics led to the improvement of the general state of the patient and normalization of the laboratory tests results. In the tenth day of hospitalization the planned endoscopic regressive cholangiopancreatography (ERCP) with papillotomy was performed. No deposits in bile ducts were revealed. The girl was recommended the procedure of cholecystectomy, which was carried out in due course without any complications.