A deficiency in growth hormone depresses growth and leads to dwarfism. The cause of hypopituitarism may be the destruction of the hypothalamus by a tumor infection or trauma. Birth trauma is often the underlying cause. Genetic forms or cerebral defects have also been described. Growth hormone may be completely lacking or partially reduced. Neurohormonal dysfunction is of particular interest. Administration, either intramuscular or subcutaneously, of human growth hormone leads initially to "catch-up" growth and to subsequent normal growth. Early treatment should be instituted if normal adult height is to be achieved.