Conventional wheeled platforms provide sufficient locomotion on smooth surfaces but are limited when contending with obstacles such as stairs, steep inclines, or rugged terrain. Legged robots, which are better suited in traversing such obstacles, require an increased number of actuators, and thereby expend more energy. This paper describes the Adaptive Wheel-Leg, AWL, that provides mobile robots with the benefits of both wheels and legs. AWL is a two degree-of-freedom, hybrid wheel-leg topology with instantaneous switching between modes. AWL provides two modes: 1) a single actuator rolling mode for smooth surfaces, and 2) a walking mode for rugged terrain. This paper presents the mechanism’s design and control methods. An experimental model and a simulation of an AWL equipped hexapod are also discussed.