Therapeutic ultrasound is already established in the treatment of diverse surgical conditions, such as cataract, liver cancer, and stones, without danger to healthy tissue. Clinical trials of catheter-delivered, high energy, low frequency (kHz) ultrasound undertaken over the last decade have demonstrated the safety of ultrasound in the treatment of peripheral and coronary artery disease, and have identified a number of indications in which it may be particularly advantageous. The dispersal of thrombus, the recanalization of chronic total occlusions, and the favorable modification of the distensibility of small, atherosclerotic vessels are three promising areas. The authors review developments in these fields.