The invention relates to an electrode assembly for electrotherapy devices. The assembly has at least one stainless steel metallic electrode and at least one electrode which is also metallic and which is covered with an insulating layer. Both of said electrodes are removably and electrically connected to a handle support in such a way that they can be actuated individually or together. The active surface area of said electrode assembly is provided with a configuration which adapts to that of the area of the patient's body to be treated. Depending on the therapy being followed, the active face of the electrodes may be static on the area of the patient to be treated or moved in order to massage said area.