Aromatase inhibitors are administered to a female patient prior to endometrial ablation or resection procedures in order to thin the endometrium to a thickness of less than 6 mm, and preferably less than 4 mm, so as to enhance the treatment outcome. Of course, administration of aromatase inhibitors would be useful for other surgical procedures on the endometrial cavity and the uterus. Commercially available aromatase inhibitors, including, the nonsteroidal preparations, anastrozole and letrozole, and a steroidal agent, exemestane, are well-tolerated, and have been shown to decrease serum estrogen levels. The aromatase inhibitor can be used alone, or in combination with other aromatase inhibitors or pharmaceutical agents, such as hormones.