An applicator of the electric type for the RF heating of living tissues is described. It consists essentially of an unbalanced capacitor where the RF current return is provided by a large groundplane electrode. A water layer is an integral part of the electric design, offering a relative independence from variations in the position of the electrodes with respect to the body being treated. The water also eleminates the detrimental effects of the high field concentrations at the edges of the hot electrode, and is additionally used for surface cooling.