Glycogen storage disease type Ia (GSD-Ia; von Gierke disease) is an inherited disorder caused by glucose-6-phosphatase deficiency, and there have been some reports of hepatic tumors in patients with this disease. We report two patients with benign hepatic tumors with GSD-Ia. One is a 19-year-old man who underwent segmentectomy 4 for a focal nodular hyperplasia, and the other is a 31-year-old woman who underwent segmentectomies 3, 5, and 6 for hepatic adenomas. Two significant perioperative complications, resulting from the carbohydrate metabolic disorders, hypoglycemia and metabolic acidosis, occurred in both patients. We managed the metabolic complications successfully by administering a sufficient volume of glucose intravenously. Close perioperative monitoring of blood glucose and lactate concentrations is essential in the perioperative management of patients with GSD-Ia. The intravenous administration of glucose, starting with a smaller dose and then increasing the dose, is adequate management for lactic acidosis with or without hypoglycemia during the perioperative period.