The issue of routine ultrasound screening is addressed through an analysis of previous randomized trials in Europe and the United States. Potential benefits of offering ultrasound examination to low risk patients are explored, including detection of anomalies, diagnosis of multiple gestation, and reduction in induced labors for erroneous diagnoses of postdatism. The most recent US routine antenatal diagnostic imaging ultrasound (RADIUS) study is summarized and analyzed. Principles of obstetric ethics as applied to the use of routine ultrasound examination are developed and discussed. The responsibilities of those involved in providing such services are described. It is our opinion that routine ultrasonography has a favorable risk to benefit ratio and suggest that it should be offered.