An electrosurgical instrument having a protective, extendable and retractable sheath or sleeve is disclosed. The sheath is disposed around and coaligned with an elongated cylindrical rod, from which extends at least one electrode. A conductor extending from the electrode is joined to a conventional power supply cord for connection to a source of RF voltage. Power supply is regulated using either a convention hand or foot switch. The sheath protects the distal electrode(s) as the instrument is inserted through a laparoscopic trocar or endoscope. It also provides an effective extension of an irrigation/aspiration lumen which extends along the length of the cylindrical rod. The proximal end of the irrigation/aspiration lumen is joined to a supply tube which either may be connected to a fluid reservoir for irrigation or to a collection reservoir for aspiration of fluids. Alternative embodiments feature alternative mechanisms for extending the sheath. In one embodiment, the sheath is retractable and shields the electrode(s) only when placed in a distal, extended position. In another embodiment, the cylindrical rod-shaped housing on which the electrode resides is retractable. When the cylindrical rod is withdrawn to a proximal, retracted position with the sheath, it shields the electrode and extends the effective end of the irrigation lumen.