Transvaginal ultrasound examination can reliably distinguish women with post-menopausal bleeding (PMB) who are at low risk of endometrial pathology (endometrial thickness < or =4 mm) from those who are at high risk (endometrium > or =5 mm) and can rule out focally growing lesions in the uterine cavity using saline infusion into the cavity as a negative contrast agent (hydrosonography). The 5 mm cut-off is applicable irrespective of the use of hormone replacement therapy. It is justified to refrain from endometrial sampling in women with PMB and an endometrial thickness of < or =4 mm because the risk of endometrial cancer in these women is low (0.1-1.0%). However, it is not known whether these women need follow-up. About 80% of women with PMB and an endometrium of > or =5 mm have focally growing pathological lesions in the uterine cavity. These should be removed by operative hysteroscopy because dilatation and curettage (D and C) will fail to diagnose and remove a large proportion of these lesions. However, D and C is a reliable diagnostic method for women without focal lesions in the uterine cavity. It is not known whether simple outpatient sampling devices (e.g. Pipelle) are as reliable as D and C in women without focal lesions. A measurement of endometrial thickness is a simple and accurate method for estimating the risk of endometrial cancer. The reliability of ultrasound evaluation of endometrial morphology and/or vascularization for risk estimation of endometrial malignancy remains to be determined.