Rabson-Mendenhall syndrome is a rare, autosomal recessive disorder affecting insulin receptor. This disorder is characterized by insulin-resistant diabetes mellitus, hyperinsulinemia, deficiency of subcutaneous fat, acanthosis nigrican, growth retardation, coarse and senile appearance, precocious puberty, and dental prematurity, enlarged genitalia, and pineal hyperplasia. Mutations of the insulin receptor gene affecting insulin action appear to be the basic mechanism underlying this syndrome. Herein, we present a case report on Rabson-Mendenhall syndrome in a 9-year-old girl.