An ultrasonic diagnostic imaging system comprising: a probe including an array of transducer elements (8, 104) having an aperture; a transmit beamformer, coupled to the array of transducer elements (8, 104), and configured to transmit in a given direction at respectively delayed times a plurality of focused transmit beams (10, 10', 10") which are laterally displaced across the aperture of the array (8, 104); a multiline receive beamformer (110a-110n), coupled to the array of transducer elements (8, 104), for receiving multiple echo signals at different lateral locations of the array of transducer elements (8, 104) and for producing a plurality of receive lines at the different lateral locations in response to each transmit beam (10, 10', 10"); a sub-aperture selector coupled to the multiline receive beamformer (110a- 110n) for selecting different sub-apertures for different look directions (LD 1, LD 2, LD 3); characterized in that the ultrasonic diagnostic imaging system further comprises: a steering circuit that includes a plurality of delays (118a-118n) for delaying the echo signals of different transmit events at each receive line and producing delayed signals, and a summer for combining the delayed signals to form retrospectively steered beams, wherein a retrospectively steered beam of a selected sub-aperture is steered by means of the delays (118a-118n) in a different look direction (LD 1, LD 2, LD 3) from beams of other sub-apertures to create received echoes from different look directions from each of a plurality of different points in the image field; a detector for detecting the received echoes of each of the steered beams to form beam signals; a combining circuit for combining the detected beam signals of the different look directions (LD 1, LD 2, LD 3) for a particular point in the image field to form speckle-reduced signals; and a display coupled to the combining circuit which produces an image with reduced speckle from the speckle-reduced signals. a probe including an array of transducer elements (8, 104) having an aperture; a transmit beamformer, coupled to the array of transducer elements (8, 104), and configured to transmit in a given direction at respectively delayed times a plurality of focused transmit beams (10, 10', 10") which are laterally displaced across the aperture of the array (8, 104); a multiline receive beamformer (110a-110n), coupled to the array of transducer elements (8, 104), for receiving multiple echo signals at different lateral locations of the array of transducer elements (8, 104) and for producing a plurality of receive lines at the different lateral locations in response to each transmit beam (10, 10', 10"); a sub-aperture selector coupled to the multiline receive beamformer (110a- 110n) for selecting different sub-apertures for different look directions (LD 1, LD 2, LD 3); characterized in that the ultrasonic diagnostic imaging system further comprises: a steering circuit that includes a plurality of delays (118a-118n) for delaying the echo signals of different transmit events at each receive line and producing delayed signals, and a summer for combining the delayed signals to form retrospectively steered beams, wherein a retrospectively steered beam of a selected sub-aperture is steered by means of the delays (118a-118n) in a different look direction (LD 1, LD 2, LD 3) from beams of other sub-apertures to create received echoes from different look directions from each of a plurality of different points in the image field; a detector for detecting the received echoes of each of the steered beams to form beam signals; a combining circuit for combining the detected beam signals of the different look directions (LD 1, LD 2, LD 3) for a particular point in the image field to form speckle-reduced signals; and a display coupled to the combining circuit which produces an image with reduced speckle from the speckle-reduced signals. a steering circuit that includes a plurality of delays (118a-118n) for delaying the echo signals of different transmit events at each receive line and producing delayed signals, and a summer for combining the delayed signals to form retrospectively steered beams, wherein a retrospectively steered beam of a selected sub-aperture is steered by means of the delays (118a-118n) in a different look direction (LD 1, LD 2, LD 3) from beams of other sub-apertures to create received echoes from different look directions from each of a plurality of different points in the image field; a detector for detecting the received echoes of each of the steered beams to form beam signals; a combining circuit for combining the detected beam signals of the different look directions (LD 1, LD 2, LD 3) for a particular point in the image field to form speckle-reduced signals; and a display coupled to the combining circuit which produces an image with reduced speckle from the speckle-reduced signals.