Tibolone is a synthetic compound with weak oestrogenic, progestagenic and androgenic properties. It does not appear to stimulate the endometrium, and therefore has appeal to the postmenopausal woman as a 'bleedfree' form of hormone replacement therapy (HRT). In the present study the vaginal cytological findings and symptoms were evaluated in 100 recently postmenopausal women, 50 of whom were started on tibolone 2.5 mg daily and 50 of whom received no medication. After 2 years in the tibolone group, cytological assessment showed a significant increase in the karyopyknotic index (P < 0.001) and maturation value (P < 0.01) whereas there was no change in the control group. Significant symptomatic improvement occurred in vaginal dryness (P < 0.001), dyspareunia (P < 0.001), sexual enjoyment (P < 0.001) and libido (P < 0.05). It is therefore concluded that tibolone has a significant oestrogenic effect on the vagina as demonstrated by vaginal cytology. In addition, improvement in the symptoms of vaginal dryness, dyspareunia, sexual enjoyment and libido occurs.