Gaining access to the peritoneal cavity through a natural orifice is potentially the next paradigm shift in minimally invasive surgery. Natural Orifice Translumenal Endoscopic Surgery (NOTES) provides distinct patient advantages, but is surgically challenging. Access to the peritoneal cavity is limited by the size and complex geometry of the natural lumen, and existing tools do not adequately address these constraints. A miniature in vivo robot with two "arms" and a central "body" has been developed for NOTES. The robot can be advanced through the esophagus and into the peritoneal cavity using an overtube and endoscope. Once completely inserted, the robot provides a stable platform for visualization and dexterous manipulation from arbitrary orientations. In vivo testing of the NOTES robot in a porcine model has been successful. Using the robot, the surgeon was able to explore the abdominal cavity and perform small bowel dissection. In addition, benchtop testing has demonstrated the ability of the robot arm to follow a predetermined path in Cartesian space and shows good results towards future three-dimensional feedback control.