The effect of estrogens on urinary incontinence in postmenopausal women was studied in order to investigate whether estrogens could cure urge incontinence in patients without detrusor hyperreflexia and whether estrogens could raise the maximum urethral closure pressure. The trial was double-blind. The cure rate in patients woth sensory urge incontinence was significantly better with estrogen than with placebo (p < 0.05, Fourfold Table Test). There were no statistically significant changes in the maximum urethral closure pressure and the functional profile length between the estrogen- and placebo-treated groups. Biopsies from the trigone showed a similar shift as in smears from urethra and vagina in the patients treated with estrogens. None of the patients had subjective side-effects and no significant changes were found in serum cholesterol or triglyceride.