We report a 19-month-old boy with Menkes' syndrome that was complicated by a progressive sliding hiatal hernia. He presented with convulsions, developmental delay, elongation and tortuosity of major cerebral arteries, and diverticulae of the bladder at 4 months of age. Based on the diagnosis of Menkes' syndrome, treatment with intravenous or subcutaneous copper-histidine administration was initiated at 6 months of age. At 13 months of age, he vomited frequently owing to sliding hiatal hernia, which progressed rapidly and required surgical treatment. Connective tissue abnormalities are characteristic complications of Menkes' syndrome. Sliding hiatal hernia is probably one of the connective tissue manifestations and should be carefully evaluated in patients with Menkes' syndrome demonstrating recurrent gastrointestinal and/or respiratory symptoms.