Endoscopic retrograde cholangiopancreatography (ERCP) is a crucial procedure for diagnosing and managing conditions affecting the pancreas and biliary tract. The procedure can be technically challenging and carries risks of complications, with post-ERCP pancreatitis (PEP) being the most common. We report a case of a 16-year-old female who presented with cholelithiasis that progressed to choledocholithiasis which was removed using ERCP. Following this, she developed PEP and subsequently progressed to atypical hemolytic uremic syndrome, a rare complication reported in the pediatric literature.