Abstract: A power vise in which a supplementary power source is used to open and close the jaws. The power vise may be actuated by a remote control, so the operator may have both hands free to hold the workpiece as it is placed in or removed from the vise and may also include a mechanism for regulating the pressure developed between the jaws. When the power source is electric, the electrically operated vise includes an output shaft of an electric motor connected to the advance screw of the vise to turn the screw and close or open the jaws. When the power source is hydraulic, the hydraulically operated vise includes a hydraulic ram, with a first jaw affixed to the hydraulic cylinder and a second jaw affixed to the piston rod of the hydraulic device. Hydraulic pressure is used to retract and extend the piston rod, thereby closing and opening the jaws.