Graves' disease (GD) is an autoimmune thyroid disease. In addition to the etiology of hyperthyroidism, TSH receptor antibodies play an important role in the pathogenesis of pretibial myxedema, ophthalmopathy, and neonatal GD. The previous epidemiological surveys have revealed that 0.08-0.6% of the population were affected by GD in Japan. Clinical signs and symptoms as well as laboratory abnormalities are described with emphasis on elevated serum VEGF and G-CSF levels in untreated GD patients. It should be noted that elderly patients may not have typical symptoms of hyperthyroidism, but cardiac symptoms and weight loss usually predominate. Abnormal laboratory findings may help to make a diagnosis in asymptomatic patients. Patients with ophthalmopathy may have antibodies to 64 kD/55 kD external orbital muscle proteins.