A workpiece regrasping system for a robot. The system includes a manipulator grippable a workpiece; a deck member having a deck surface on which a workpiece is placeable; a support mechanism rotatably supporting the deck member about an axis parallel to the deck surface; a workpiece-orientation control section for controlling the manipulator so as to grip a workpiece at a first point of the workpiece and to bring the workpiece into abutment with the deck surface of the deck member, and configured to displace the workpiece together with the deck member about the axis, while maintaining a mutually abutted condition, until the workpiece occupies a desired orientation, with at least a part of a weight of the workpiece being carried on the deck surface; and a regrasping control section for controlling the manipulator so as to temporarily release the workpiece placed on the deck surface in the desired orientation and to regrasp the workpiece at a second point different from the first point. The workpiece-orientation control section may control an operation of the manipulator, or control a rotational drive section for the deck member, while maintaining the workpiece in abutment with the deck surface, to displace the workpiece to the desired orientation.