Vasomotor symptoms after menopause are multifactorial in origin but result primarily from the loss of estrogen as ovarian function ceases. Although hot flushes typically last for 0.5 to 5.0 years after natural menopause, they may persist for as long as 15 years in a small percentage of postmenopausal women. In contrast, hot flushes tend to last longer and be more severe in surgically menopausal women. One of the major complaints associated with vasomotor symptoms is insomnia, which can have a domino effect on the patient's overall quality of life. Conventional hormone replacement therapy is effective in controlling vasomotor symptoms, including insomnia, for most postmenopausal women. However, data suggest that estrogen-androgen replacement therapy provides additional relief for women with persistent or severe vasomotor symptoms, especially women scheduled to undergo surgical menopause.