Macroamylasemia is a benign condition characterized by abnormally large-sized serum amylase; it has been reported to occur in 1-2% of the population. In macroamylasemia, a macromolecular complex consisting of amylase linked to immunoglobulins circulates in the plasma and usually causes hyperamylasemia with low or normal amylasuria. Macroamylasemia is extremely rare in children. We report a case of a 4-year-old girl with abdominal pain and macroamylasemia, who was initially misdiagnosed as having acute pancreatitis. Failure to immediately identify macroamylase as the cause of the unexplained but benign hyperamylasemia can lead to the misdiagnosis of the condition, necessitating costly analyses for ruling out pancreatic disease and unnecessary prescriptions such as fasting and intravenous replacement therapies, as was observed in our patient.