In this paper, control of an underactuated two-wheeled mobile manipulator using backstepping method is considered. Two-wheeled systems have many advantages compared to the statically stable systems. Mobile manipulators with two wheels have smaller footprints, which makes them more flexible and agile than the statically stable mobile manipulators. However, two-wheeled mobile manipulator is an underactuated system because of a passive joint. Therefore, it is required to stabilize the passive joint and control the position of center of gravity of the manipulator. To realize this, nonlinear backstepping based control method with a virtual double inverted pendulum is proposed in this paper.