Threedimensional ultrasound has really developed seriously in the last years.The purpose of this lecture will be to evaluate the added value to normal prenatal diagnostic ultrasound.The different aspects of 3-D will be reviewed: The differences in multiplanar imaging and the different rendering possibilities.Many think 3-D is nothing more than making nice pictures.It has been shown that it improves significantly the parental bonding (S.Campbell), but the main advantage of 3-D imaging lies in the possibility to view planes that are not possible with conventional 2-D ultrasound.