An impedance feedback electrosurgical system is useful with electrosurgical tools to maintain a substantially constant level of current within the tissue in contact with the tool. The system comprises active and return electrodes associated with an electrosurgical tool, an impedance monitoring device and a power control unit. Energy sufficient to affect tissue is delivered through the active electrode to tissue and to the return electrode. The impedance measuring device is in circuit with the return electrodes and measures the impedance of tissue. A signal representative of tissue impedance is communicated from the impedance measuring device to the power control unit. The power control unit adjusts the energy applied to tissue to maintain tissue impedance within a preselected and desired range.