Precocious puberty is difficult to define because of the marked variation in the age at which puberty begins normally, onset of puberty before 8 years of age in girls and 9 years in boys may be considered precocious. The etiology of precocious puberty in boys is usually idiopathic, but can result from adrenal and testicular tumors. The hepatoblastoma that produces hCG is a very rare functioning tumor known to cause precocious puberty in boys. Recently, author experienced one case of virilizing adrenal cortical adenoma in 22 month-old boy, one case of adrenal cortical carcinoma in 28 month-old boy, and one case of virilizing hCG-producing hepatoblastoma in 7 year-old boy and reviewed literatures.