An electrosurgical generator has output terminals for connection to active and return electrodes respectively of an electrosurgical instrument and, connected to the output terminals via at least one isolation capacitor, a radio frequency (r.f.) source which may be pulsed by a pulsing circuit. To permit tissue removal at a high rate, the source and the pulsing circuit are arranged so as to generate a pulsed r.f. output signal having a peak-to-peak voltage of at least 1250V, a mark-to-space ratio not more than 1:1, and a pulse length not more than 100 mu s. A continuous RF wave applied to the cutting electrode would in fact rapidly bring the electrode to high operating temperatures which could cause electrode destruction since the rate at which heat is accumulated on to the electrode would be higher that the heat dissipation rate in the operating environment.; The pulsed RF wave allows during the off periods for heat dissipation, temperature decrease, thus electrode conservation and higher peak power thus higher cutting speeds.