OBJECTIVE To assess the efficacy and safety of intravaginal estriol administration on urinary incontinence, urogenital atrophy, and recurrent urinary tract infections in postmenopausal women. METHODS Eighty-eight postmenopausal women with urogenital aging symptoms were enrolled in this prospective, randomized, placebo-controlled study. Participants were randomly divided into two groups, with each group consisting of 44 women. Women in the treatment group received intravaginal estriol ovules: 1 ovule (1 mg) once daily for 2 weeks and then 2 ovules once weekly for a total of 6 months as maintenance therapy. Women in the control group received inert placebo vaginal suppositories in a similar regimen. We evaluated urogenital symptomatology, urine cultures, colposcopic findings, urethral cytologic findings, urethral pressure profiles, and urethrocystometry before as well as after 6 months of treatment. RESULTS After therapy, the symptoms and signs of urogenital atrophy significantly improved in the treatment group in comparison with the control group. Thirty (68%) of the treated participants, and only seven (16%) of the control participants registered a subjective improvement of their incontinence. In the treated participants, we observed significant improvements of colposcopic findings, and there were statistically significant increases in mean maximum urethral pressure, in mean urethral closure pressure as well as in the abdominal pressure transmission ratio to the proximal urethra. Urethrocystometry showed positive but not statistically significant modifications. CONCLUSIONS Our results show that intravaginal administration of estriol may represent a satisfactory therapeutic choice for those postmenopausal women with urogenital tract disturbances who have contraindications or refuse to undergo standard hormone therapy.