A system for performing minimally invasive cardiac procedures. The system includes a pair of surgical instruments that are coupled to a pair of robotic arms. The instruments have end effectors that can be manipulated to hold and suture tissues. The robotic arms are coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed by the surgeon. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient's skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft.