This is a multicentre study from Europe. The female genitals and lower urinary tract have a common embryological origin arising from urogenital sinus. Therefore, both could be sensitive to female sex steroid hormones. Oestrogens and progesterone receptors have been demonstrated in the vagina, urethra, bladder and pelvic floor musculature. For many years, systemic and vaginal oestrogen therapy was considered beneficial but recently this view has been challenged. This article aims to provide evidence (or otherwise) of oestrogen therapy in overactive bladder (OAB) and urinary incontinence. Pros and cons of systemic and vaginal oestrogens are mentioned. Low-dose vaginal oestrogens are estrone (E1), estradiol (E2) and estriol (E3). Most potent out of the three is estradiol. Combination therapy with vaginal oestrogens and anti-cholinergic drugs may have some role in post-menopausal women with OAB. However, based on current studies, vaginal oestrogens themselves have no effect on post-menopausal stress incontinence.