STUDY OBJECTIVE--The aim was to describe changes in the use of hormone replacement therapy (HRT) in Finland during the period 1976-1989. DESIGN--The study involved four separate cross sectional population surveys in the years 1976, 1978-1980, 1987, and 1989. Three of them involved interviews and one a questionnaire. Sales figures of hormones in 1981-1989 were used. PARTICIPANTS--Participants were national samples of non-institutionalized Finnish women 45-64 years of age. Participation rates ranged from 85% to 96%. MEASUREMENTS AND MAIN RESULTS--Current reported hormone use in the surveys of 1976, 1978-1980, and 1987 was assessed, together with reported hormone use in the last month in the 1989 survey. During the study period the proportion of HRT users increased fivefold. In 1989, 20% of women reported current use of HRT, and the highest rate of use was found among 50-54 year old women in the Helsinki area. In 1976, users were mainly women around the age of menopause, those living in the capital area, and those having a rather high level of education. By 1989 use had spread to postmenopausal women, those in rural areas, and those with less education. CONCLUSIONS--Use of HRT has increased in Finland. It is difficult to evaluate whether the level of current use is too high, optimal, or too low, because recommendations are contradictory and the long term effects of HRT are unkown.