Objective: To evaluate the efficacy of three doses of estrogen/progestin therapy for relief of vasomotor symptoms (VMS) and vaginal atrophy in Asian women of different ethnic background; to examine differences in prevalence of VMS among ethnic groups. Methods: A prospective, randomized, double-blind multinational clinical trial in healthy postmenopausal women from 11 Asian countries. Following 2 weeks of baseline observations, the women received one of three conjugated estrogens (CE)/medroxyprogesterone acetate (MPA) doses (in mg) daily for 24 weeks: 0.625/2.5; 0.45/1.5; or 0.3/1.5. The women recorded VMS and uterine bleeding daily on diary cards translated into 10 languages. Vaginal responsiveness was evaluated by the vaginal maturation index (VMI) at baseline and at week 24. Results: The study population consisted of 1028 postmenopausal women. The VMS-evaluable subpopulation was about 60% of the total population. The mean baseline hot flush frequency was 1.6 flushes/day (613 women). Hot flush frequency decreased significantly in all dose groups within 4 weeks of treatment. The VMI shifted significantly from immature (parabasal) to mature (superficial) cells at end of treatment. The therapeutic responses were comparable in all three groups. However, uterine bleeding was consistently less frequent in the 0.3/1.5 mg group. The percentage of women who reported VMS at baseline differed substantially among the different ethnic groups, ranging from 5% in Indonesian women to 100% in Vietnamese women. Conclusion: Asian postmenopausal women respond to CE/MPA therapy. The lowest dose is as effective for VMS and vaginal responsiveness as the higher doses, and the lowest dose is associated with the most favorable bleeding pattern. The prevalence of vasomotor symptoms differs among ethnic groups.