A system for ablating tissue includes an ablation catheter for insertion into the body of a patient and a robotic controller for moving the catheter within the body. The robotic controller advances the catheter until the catheter contacts the tissue surface, maintains contact between the catheter and the tissue surface, and moves the catheter along a predetermined path to create a substantially continuous lesion of ablated tissue. A display device may be used to present a graphical representation of an area of tissue to be ablated. A user interface permits selection of a plurality of treatment points on the graphical representation. The interface is preferably coupled to the controller and catheter such that the controller may cause the catheter to automatically ablate tissue at and between the plurality of treatment points in response to the received user input.