This prospective study was designed to investigate the effects of hormone replacement therapy (HRT) on systolic and diastolic functions. Twenty-eight non-smoking, healthy postmenopausal women who had not received any kind of HRT for at least three years within the onset of menopause were included in the study. Ail patients received 0.625 mg conjugated oestrogens and 2.5 mg medroxyprogesterone acetate as daily HRT regimen. Their basic systolic and diastolic functions were investigated echocardiographically using standard positions and windows before and 6 months after initiation of HRT, The means of age, weight and length of postmenopausal period were 49.3 +/- 5.8 years, 63.5 +/- 8.7 kg and 46.3 +/- 7.1 months, respectively, Heart rate and systolic and diastolic pressures were similar during the pre- and post-treatment periods. After 6 months of HRT, the mean left ventricular end-systolic and end-diastolic volumes were decreased significantly (71.3 +/- 16.4 versus 56.3 +/- 22.8 mi, 144.5 +/- 26.1 versus 111.7 +/- 24.0 mi, respectively, P <0.05), Left ventricular ejection fraction was increased (45.1 +/- 6.2% versus 54.8 +/- 4.1%, P < 0.05), Improvement in diastolic function was significant compared with the pretreatment period (E/A 0.90 +/- 0.2 versus 1.10 +/- 0.4, deceleration time 238 +/- 36.8 versus 201 +/- 24.2 ms, respectively, P < 0.05), Based on our preliminary results, we conclude that besides the known favourable effects on women's lives, HRT may also improve cardiac performance and age-related dysfunctions. The present results further suggest that oestrogens exert many direct effects on the cardiovascular system, other than the metabolic changes related to lipoproteins.