An ablation electrode assembly operatively connectable to a source of electrosurgical energy and to a source of cooling fluid, the ablation electrode assembly comprising: a hub defining a chamber therein; at least one electrically conductive ablation needle extending from the hub, the needle being cylindrical and defining cavity therein, wherein the cavity of the ablation needle extends to the distal end portion of the needle and the ablation needle including a distal end portion configured to penetrate tissue, said distal end portion of the needle being electrically and thermally conductive for establishing electric and thermal communication with the tissue; a heat sink fabricated from an anisotropic material disposed within the cavity operatively connected to the ablation needle, wherein a distal end of the heat sink is in conductive engagement with a distal end surface of the cavity of the ablation needle, the heat sink being connected to the ablation needle to draw energy away from at least the distal end portion thereof, the heat sink including a proximal end extending into the chamber of the hub; an inlet conduit fluidly connected to the hub for delivering fluid into the chamber thereof from the source of fluid, wherein the fluid withdraws energy from the proximal end of the heat sink, an outlet conduit fluidly connected to the chamber of the hub for delivering fluid from the chamber thereof,, such that fluid enters the chamber of the hub through the inlet conduit and exits the chamber of the hub through the outlet conduit, whereby fluid contacts and washes over or across the proximal end of the heat sink and withdraws heat and/or energy therefrom and, in turn, from the ablation needle. a hub defining a chamber therein; at least one electrically conductive ablation needle extending from the hub, the needle being cylindrical and defining cavity therein, wherein the cavity of the ablation needle extends to the distal end portion of the needle and the ablation needle including a distal end portion configured to penetrate tissue, said distal end portion of the needle being electrically and thermally conductive for establishing electric and thermal communication with the tissue; a heat sink fabricated from an anisotropic material disposed within the cavity operatively connected to the ablation needle, wherein a distal end of the heat sink is in conductive engagement with a distal end surface of the cavity of the ablation needle, the heat sink being connected to the ablation needle to draw energy away from at least the distal end portion thereof, the heat sink including a proximal end extending into the chamber of the hub; an inlet conduit fluidly connected to the hub for delivering fluid into the chamber thereof from the source of fluid, wherein the fluid withdraws energy from the proximal end of the heat sink, an outlet conduit fluidly connected to the chamber of the hub for delivering fluid from the chamber thereof,, such that fluid enters the chamber of the hub through the inlet conduit and exits the chamber of the hub through the outlet conduit, whereby fluid contacts and washes over or across the proximal end of the heat sink and withdraws heat and/or energy therefrom and, in turn, from the ablation needle.