Hormone replacement therapy (HRT) is used for relief of symptoms related to the menopause and for the prevention of postmenopausal osteoporosis and cardiovascular disease. Patterns of use of HRT are thought to be changing rapidly, but little is known about who is using the therapy, for what purpose or for what period of time. Telephone interviews were conducted in May 1991 with a randomly selected sample of 2001 Australian-born women aged 45 to 55 years living in Melbourne, as part of the Melbourne Women's Midlife Health Project. Questions related to use of HRT, health status, use of health services, sexual functioning, attitudes to menopause and aging, and sociodemographic characteristics. Twenty-one per cent of the sample were using HRT. Use was more prevalent among women 50 years and over (28 per cent) than those under 50 (15 per cent). Seventeen per cent of nonhysterectomised women, 31 per cent of hysterectomised women and 49 per cent of women who had undergone hysterectomy and bilateral oophorectomy were current users. Almost 60 per cent had been using the therapy for two years or less, and 34 per cent for one year or less. Just over half reported control of hot flushes as a benefit, and 10 per cent mentioned prevention of bone loss as a benefit. Logistic regression analysis identified differences between users and nonusers in experience of hot flushes, health status, use of preventive and treatment services, sexual functioning, wellbeing, attitudes to menopause and aging, and sociodemographic characteristics. These differences may relate to risk of later cardiovascular disease.