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. Prospective, open label, single center, randomized trial. The menopause clinic, Centre Universitaire de Santé de l'Estrie, Université de Sherbrooke, Quebec, Canada. Fifty-nine postmenopausal women seeking treatment for symptomatic menopause. 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. Six 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 < or = 4 mm and histologic diagnosis of endometrial atrophy was found in 41 of 53 patients. In both groups the climacteric symptoms were improved and the lipid profile showed a beneficial effect. 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%).