Objective: To compare two different continuous regimens of estrogens: conjugated estrogens or estrone sulfate with medroxyprogesterone acetate (MPA). To evaluate the impact of these two regimens on bleeding pattern, endometrial histology, lipid metabolism, and climacteric symptoms. Design: Prospective, open label, single center, randomized trial. Setting: The menopause clinic, Centre Universitaire de Sante de l'Estrie, Universite de Sherbrooke, Quebec, Canada. Patient(s): Fifty-nine postmenopausal women seeking treatment for symptomatic menopause. Intervention(s): Patients were randomized to two groups. Both groups received 2.5 mg/d MPA plus 0.625 mg/d conjugated estrogens (group A: 31 patients) or 0.625 mg/d estrone sulfate (group B: 28 patients). Lipid metabolism, endometrial biopsies, and endometrial thickness (measured by vaginal ultrasound) were determined at 52 and 104 weeks. Result(s): Sis women (10%) withdrew from the study (irregular bleeding and side effects). Fifty-three patients completed the study. Amenorrhea was produced in 92.6% and 96.1% by 52 weeks, and 100% by 104 weeks for groups A and B, respectively. Endometrial atrophy was observed by histology in 92.4% by 52 weeks and in 100% by 104 weeks in both groups. The correlation between an endometrial thickness (vaginal ultrasound) of less than or equal to 4 mm and histologic diagnosis of endometrial atrophy was found in 41 of 53 patients. Ln both groups the climacteric symptoms were improved and the lipid profile showed a beneficial effect. Conclusion(s): No significant difference was found between the two continuous regimens. Amenorrhea and atrophic endometrium occurred in 92.4% after 52 weeks of treatment. A favorable change in lipid metabolism even with the addition of MPA to estrogens was noted. Irregular bleeding was reduced and the long-term compliance with the continuous regimen was high (90%).