Objective: Tibolone has been shown to alleviate climacteric symptoms. This study was designed to compare the effect of tibolone (Livial , 2.5 mg daily) on different climacteric complaints and its impact on the endometrium, determined by vaginal ultrasound, with that of conjugated estrogens (Premarin , 0.625 mg daily) continuously for 6 months in combination with the progestogen medrogestone (Colpron , 2 5 mg daily for 12 days each month). Methods: One hundred and twenty-nine postmenopausal women were recruited and the severity of climacteric symptoms as well as endometrial thickness were recorded at the pre-trial examination and after 1, 3, and 6 months. Results: With the exception of vertigo, mood depression, mood disorder, loss of libido, and dryness of skin, where tibolone was found to be more effective than conjugated estrogens/medrogestone, climacteric symptoms improved significantly in both groups over the 6-month study period. Endometrial thickness did not increase significantly in the tibolone group, whereas in the conjugated estrogens/medrogestone group there was a highly significant increase after 1 month and still a trend towards significance after 6 months. Recurrence of vaginal bleeding occurred significantly less frequently in the tibolone group than in the comparison group. Conclusion: Tibolone seems to offer a complete treatment of the climacteric complaints whilst avoiding some of the problems associated with classical hormone replacement therapy.