One case of ovarian tumor associated with precocious puberty is reported in this communication. It is considered to be a typical granuosa cell tumor. From a review of The literature and a study of my case, I have no doubt that important advancemnts will be made, particularly with regard to the hormonal studies of this group of neoplasms. Functioning tumors of the ovary which were formerly unrecognized, today represent a subject of such broad possibilities as to be of ]interest to the medical profession in general. From an endocrinologie viewpoint, these tumors furnish definite evidence of hormonal production and its clinical effects. To the embryologist, thevarious phases of cellular didderentiation are of especial internist. The identification of these unusual tumors stirs the interest of the internist. The pathologist's, as well as the surgeon's interest is concentrated upon the difficult problem of confirming the clinical diagnosis and choosing a proper course of treatment. The general interest in the study of these tumors has been stimulated to such a degree that a positive diagnosis is more likely in the majority of cases. Consequently, through proper diagnosis, pathologic confirmation and proper treatment, the prognosis today is, more favorable than in the past.