The argon, carbon dioxide and neodymium-YAG lasers have been proposed as effective instruments for surgical procedures of the intact cardiovascular system. While argon and CO2 lasers cause superficial (0 to 1 mm) thermal injury, the Nd:YAG laser is better suited for effecting deep thermal necrosis (3 to 4 mm). Microsurgical vessel anastomoses can be done by “tissue welding” with any of the three clinical lasers. Myocardial revascularization may be accomplished by drilling “neocapillaries” in ischemic myocardium. Endocardial resection for destroying arrhythmic pathways and removing hypertrophied septal muscle has also been successfully accomplished with laser phototherapy. Last, laser-mediated vaporization of atherosclerotic plaque in the coronary arteries and peripheral circulation may offer a percutaneous approach to the treatment of arterial occlusive disease. Cardiovascular uses of lasers are purely investigational at the current time. Much more needs to be known before widespread clinical use of lasers in the cardiovascular system can occur.