Without doubt, the B-mode imaging is the most important examination method in prenatal ultrasound. Well over 90% of detectable congenital anomalies can be recognised using the two-dimensional realtime imaging method. Hence, paramount importance is certainly ascribed to the quality of the B-mode image in an ultrasound system. In addition, other ultrasound modalities help us to considerably enhance diagnostic reliability. Colour Doppler definitely ranks first among these supplementary techniques. Using colour, defined blood vessels can be identified and can then serve as a landmark for detection of organs. We also use colour Doppler in fetal echocardiography, where this method has proved to be an important diagnostic instrument. Furthermore, we use colour in fetomaternal Duplex sonography.