Seventy-four postmenopausal women presenting with vaginal atrophy were treated with either Ovestin vaginal cream (Group A, 23 women: 1 mg/day E3; Group B, 30 women: 0.5 mg/day E3) or vaginal suppositories (Group C, 21 women: 0.5 mg/day E3), applied daily for 3 wk (A and B) or 2 wk (C) before retiring. Ten women from A and 10 from B applied a maintenance dose (1 application twice weekly) during wk 4-16. Effects on vaginal cytology, cervical mucus and clinical and colposcopic findings were studied. Endometrial biopsies were done in 16 patients (A) before and after 3 wk of treatment, and, in 8 of the cases, at 16 wk. A routine laboratory screening program was performed before and after 16 wk of treatment in 10 patients (A). Plasma samples for hormone level determinations were obtained in 32 patients. Clinical and colposcopic findings showed a beneficial effect of treatments, confirmed by vaginal smears, and persisting during maintenance therapy. Effect on cervical mucus was slight to moderate. No side effects occurred and tolerance was very good. Endometrium remained atrophic under treatment. Screening program revealed no abnormalities. Treatments induced a sharp rise in plasma E3, followed by a gradual decline. Gonadotropins were slightly suppressed. E1, E2, PRL and SHBG capacity remained unchanged.