OBJECTIVE Our purpose was to study the efficacy, safety, and acceptability of a new estradiol-releasing (6.5 to 9.5 micrograms per 24 hours) silicone rubber vaginal ring compared with Ovesterin 0.5 mg estriol vaginal pessaries. METHODS Gynecologic clinical status, vaginal pH, cytologic characteristics, and occurrence of bacteriuria were determined before starting and after 3 and 12 weeks of treatment in 146 postmenopausal women. RESULTS Both treatments alleviated the subjective and objective symptoms of estrogen deficiency excellently, and both were equally effective at restoring the vaginal pH to levels normally seen in fertile women (< 5.5). Vaginal cytologic studies showed a significant difference in maturation value in favor of the estradiol-releasing silicone rubber vaginal ring, as measured by the pathologist's assessment of the proliferation of the vaginal mucosa. A total of 77% of users were classified as responders, compared with 39% in the pessary group. Both treatments were well accepted. The administration of the pessary was associated with a significantly higher (p < 0.001) incidence of discomfort than that of the ring, which was given better (p < 0.001) rating by the patients at the 12-week visit. A strong preference (p < 0.001) for the ring was shown by patients with previous experience with pessaries. CONCLUSIONS Treatment of urogenital symptoms in postmenopausal women with an estradiol-releasing vaginal ring is shown to be an effective and safe method, exhibiting advantages over treatment with estriol vaginal pessaries.