Serum FSH, LH and oestrone levels were determined in postmenopausal women before and at 1, 3 and 6 months after the onset of cyclical treatment with 0.05 mg of ethinyl oestradiol (n = 19) or 2 mg of oestradiol valerianate (n = 20). Most samples from the women taking oestradiol valerianate were also analyzed for oestradiol. Vaginal smears were obtained from all patients. Although all women were relieved of vasomotor symptoms, the FSH levels usually exceeded the fertile range. Ethinyl oestradiol reduced FSH by 70 to 75 per cent and LH by 30 to 40 per cent while oestrone was increased by 20 to 40 per cent. In the women taking oestradiol valerianate, FSH and LH levels were both reduced by 20 to 25 per cent wheras serum oestradiol increased by 200 to 300 per cent and oestrone increased by 600 to 700 per cent. The mean vaginal maturation value rose equally in the two groups but 40 per cent of the patients in both groups showed no change in the value. There was no correlation between the appearance of vaginal endocrine smears and hormone levels.