A new approach to laparoscopic surgery involves placing a robot completely within the patient. These in vivo robots are then able to provide visual feedback and task assistance that would otherwise require additional incisions. Wheeled in vivo robots can provide a mobile plat form for cameras, graspers, and other sensory devices that assist in laparoscopy. Development of wheeled in vivo mobile robots was achieved through a design process that included modeling, finite element analysis (FEA), bench top testing, and animal tests. Laboratory testing using a wheel test platform identified a helical wheel design as the best candidate. Finite element simulations were then used to better undertand how changing the helical wheel geometric parameters affected drawbar force. Several prototype mobile robots were then developed based on these results. The drawbar forces of these robots were measured in the laboratory to confirm the FEA results. Finally, these robots were successfully tested during animal surgeries. Copyright © 2007 by ASME.