Acute pancreatitis is an emerging problem with an incidence between 3.6 and 13.2 cases/100,000 children. However, necrotizing pancreatitis (necrosis greater than 30% of the pancreas and/or greater than 3 cm in an area of the pancreas) is a rare condition (<1% of acute pancreatitis), with a presentation similar to not complicated pancreatitis cases and with high morbidity and mortality. Computed tomography allows an assessment of the severity of the disease and the risk of complications (Balthazar Score). Not complicated pancreatitis cases have a favorable outcome, but necrotizing pancreatitis cases require intensive medical treatment and sometimes surgical treatment. We report the case of an 11 year-old boy with clinical presentation compatible with acute pancreatitis and confirmed by abdominal ultrasonography. Due to worsening of laboratory test, an abdominal computed tomography was performed showing a necrotizing pancreatitis and large pseudocysts. Close monitoring and a conservative approach was adopted, with clinical and analytical improvement. After one year follow-up, the patient is asymptomatic, normal ancillary tests and no evidence of pancreatic pseudocyst. The pediatric necrohaemorragic pancreatitis is an uncommon and potentially severe entity; we must keep this complication in mind for an adequate differential diagnosis of acute abdomen.