An ultrasonic diagnostic imaging system and method are described in which spatially compounded images are produced by transmitting ultrasound beams in different directions during a common transmit-receive interval. Echoes are received from the different beam directions and are beamformed by a multiline beamformer to produce differently steered beams of coherent echo signals. The echoes are combined on a spatial basis with echoes from different look directions which correspond to the same spatial location being combined. The resulting spatially compounded image is displayed.