Glycogen storage disease type IV (GSD-IV) is a rare autosomal recessive disease caused by deficient glycogen branching enzyme (GBE). We report a 15-month-old female patient with GSD-IV who exhibited an abdominal distension and failure to thrive for 9 months. The patient showed hepatosplenomegaly with massive ascites. The laboratory findings showed abnormal liver functions including prolongation of prothrombin time and partial thromboplastin time. The light microscopic and electron microscopic findings of the liver biopsy specimen were consistent with GSD-IV. Measurement of glycogen quantity in the red blood cells showed increased storage of glycogen in the patient and interestingly, in her mother. The GBE activity of the patient's red blood cells was undetectable. The patient's ascites, general condition, and laboratory findings have been improved with supportive treatment with diuretics and a low dose of prednisolone.