Menopause (cessation of menstruation) and the period surrounding it (climacterium) are often defined retrospectively by asking a woman the date of her last menstrual period (LMP). Based on a survey of 2000 women aged 45-64 in 1989 in Finland, this study examines (1) the relation between these definitions and women's own definition of their climacteric status and of the cessation of menstruation and (2) the effect of menopausal and postmenopausal hormone therapy and hysterectomy on the definition of menopause and climacterium. Agreement of the woman's own definition of her climacteric status and interval since LMP was 25% among current hormone users, 41% among hysterectomised women and 64% among those who were neither currently using hormones nor had been hysterectomised. Current hormone users defined the climacteric phase as longer than their LMP suggested. Current hormone use and hysterectomy had little effect on reported final cessation of menstrual periods. It is concluded that hysterectomy and hormone therapy shape women's thinking about the end of reproductive life, blur the concepts of menopause and postmenopause and confuse the measurement of age at menopause.