The scale of wind turbines has continuously increased over the last decade. Especially, the rapid growth of the rotor diameter has brought about the increase of the tower height and the load on the rotor blade, as can be seen in the case of a 5MW class wind turbine with 126m rotor diameter. This trend means the increasing possibility of system failure. In addition to that, it is impossible for human operators to stay and manage all the turbines in the case of a large-scale wind farm. For these reasons, the operation and maintenance technology is getting more importance. In this paper, we present an unmanned remote monitoring system for MW class wind turbines and its application to YeungHeung wind test bed.