Glycogen storage disease type I (GSD-I) is an inherited disorder that is due to a glucose-6-phosphatase (G6Pase) deficiency. There have been recent reports of hepatocellular tumors in adults with this disease. Hepatic adenoma is the most common tumor described but others, including hepatocellular carcinomas, hepatoblastomas, and focal nodular hyperplasia (FNH) have been reported. FNH of the liver is a rare benign lesion that has been reported in eight patients with GSD-I. Three of these eight patients, in addition to the patient in our study, had been treated with portacaval shunts. When these patients were compared with patients who had not received such treatment, it appeared that the portacaval shunts may have induced the development of FNH and may have been associated with earlier complications. FNH is a benign tumor that may coexist with adjacent fibrolamillar carcinomas and/or adenomas and requires careful follow-up.