A total of 230 apparently healthy postmenopausal women underwent transvaginal sonography and pelvic examination. The mean ovarian volume was 3. 1 cm(3) with a range of 0.4-57.4 cm(3) and fewer than 5% (4.8%) of the subjects had a mean volume exceeding two standard deviations of the sample mean. Transvaginal sonography successfully imaged 64% of reported ovaries overall, although the proportion of ovaries imaged varied by sonographer. The poorer imaging rates found in this study, as compared with some previous investigations using transabdominal sonography, could be due to several factors including the type of sonography, the type of sample, the scanning time, and/or the criteria used to identify an ovary. Transvaginal sonography offers practical advantages over transabdominal sonography, but the potential loss in sensitivity, due to non-visualization of a substantial proportion of ovaries, must be formally assessed before adopting transvaginal sonography more widely as the primary screening modality.