The aromatase inhibitor anastrazole proved effective in the treatment of endometrial hyperplasia and postmenopausal bleeding in an obese 65-year-old woman with high operative risk. During anastrazole administration for 12 months, the endometrial thickness decreased from 9.8 mm to 2.4 mm and the control endometrial histology showed an atrophic endometrium. Uterine bleeding did not occur in the post-treatment, 3-year follow-up period. The endometrial thicknesses measured yearly by ultrasonography were 2.9, 3.5 and 3.3 mm. The plasma estradiol levels increased from < 73 pmol/l post-treatment to 112, 98 and 103 pmol/l. This case demonstrates that long-term aromatase inhibitor treatment can result in a refractory status of the endometrium and the estradiol produced in the adipose tissue does not exert a proliferative effect.