Transvaginal ultrasound examination can reliably distinguish women with post-menopausal bleeding (PMB) who are at low risk of endometrial pathology (endometrial thickness less than or equal to 4 mm) from those who are at high risk (endometrium greater than or equal to 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 less than or equal to 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 greater than or equal to5 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((R))) 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.