Thyrotoxicosis secondary to Graves' disease developed in a 3-year-old black boy with no previous history of thyroid disease. Thyrotoxicosis is a rare disorder of childhood that is characterized by an accelerated metabolism of body tissues which results from the stimulation of thyroid gland activity induced through a variety of autoantibodies. Historically, less than 5% of all incidents of Graves' disease occur in childhood, and recent studies show an incidence as low as 0.000001%. It is three to eight times more prevalent in females than in males and increases in incidence throughout childhood and adolescence. More than two thirds of childhood cases occur between the ages of 10 and 15 years. A review of the medical literature illustrates that less than 2% of hyperthyroid children in recorded cases are younger than 4 years. Records from Children's Hospital of Oklahoma in Oklahoma City support the unusual nature of this case, the hospital having seen only three children younger than 4 years requiring thyroid ablation therapy in 17 years. Physicians should consider Graves' disease in any child with clinical manifestations of hyperthyroidism, regardless of the age.