The uterine leiomyomatosis represents the largest amount of tumors of the uterus, and the treatment in most of the cases is surgical. This tumor of smooth muscle has been associated with the stimulus given of sexual steroids, mainly estrogens. Several analogues by the hypothalamic hormone liberating gonadotropins (GnRH) show an stimulating-inhibiting action upon hypophyseal gonadotropins secretion (LH-FSH), variable effect on ovarian steroidogenesis, depending on the dose and frequency of use. When the decapeptide is used daily and during more than a month, it may block the production of LH, FSH and estrogens, and produces amenorrhea. As uterine myomatosis is a condition that may depend on estrogens, it was decided to treat with an analogue of GnRH (Intranasal Buserelin Acetate), one patient, 28 years old with clinical, histopathologic and ultrasonographic of uterine myomatosis, who presented manifestations of hypochromic, microcytic anemia by frequent intermenstrual bleedings. The application of GnRH analogue was done daily during eight months. The therapeutical result control of the tumor was done by an ultrasonographic study and with hysterosalpingography, before and after. The treatment was stopped because there was a significant diminution in the tumor size and bleeding disappearance. Two months of follow up have not shown changes.