The first paper concerning the use of ultrasound in soft tissue exploration was published in 1942. From that, following a logarithmic curve, ultrasound has become the main exploration technique in obstetrics and gynecology, essentially due to the absence of side-effect. In obstetrics, a new knowledge of the embryo and the fetus has been obtained. The morphology of the conceptus along the intrauterine life is more precisely defined. The fetal well-being and its metabolic function can be approached by the real time imaging and Doppler application. In gynecology, ultrasound has become the first imaging technique orientations, when mediet, the use of the others.