In the fifteen years since medical diagnostic ultrasound has become widely available, several trends have emerged. First, pulse-echo technology has supplanted all competing acoustic mechanisms. Second, packaging and display modes have become increasingly important. Certain specialized types of systems, such as dedicated A-mode or M-mode scanners, have been replaced by more versatile B-mode imaging systems configured to meet specific clinical needs. Finally, signal processing techniques, either image enhancement or non-image analysis and tissue characterization, are receiving increased attention. Innovation seems to be moving from acoustic issues to packaging and processing issues. While dramtic improvements in image quality are still possible and probable, changes in the next few years may be less acoustic oriented than packaging and processing specific.