An implantable catheter that can be electrochemically disinfected in situ in the absence of an added biocidal agent without removal of the implanted catheter from the body of the patient by creating a biofilm-inhibiting concentration of oxidizing agents from endogenous compounds present in the body without causing significant damage to cells and tissues that are not associated with the biofilm, the catheter comprising: an elongate catheter body comprising a dielectric material having a proximal end, a distal end, a lumen extending through the catheter body and adapted to transport fluid from the proximal end to the distal end, an outer surface on the exterior of the catheter body, and an inner surface on the interior of the lumen; two exterior electrodes (66, 68) on and integral with the outer surface of the catheter, the exterior electrodes being elongate and extending longitudinally along the outer surface of the catheter body from the proximal end to a distal terminus at the distal end and being adapted for applying a voltage across the exterior electrodes of a magnitude that is effective to create a biofilm- inhibiting concentration of oxidizing agents from endogenous compounds present in the body; wherein the electrodes extend radially inward from the outer surface through a wall of the catheter body to the inner surface, thereby additionally serving as interior electrodes; wherein the two exterior electrodes are separated by a pair of gaps (71, 73), each gap comprising the dielectric material of the catheter body, and extending radially from the outer surface to the inner surface of the catheter body and longitudinally from the proximal end to the distal end; and a means for receiving the voltage from a voltage source so that an electric field is generated across the at least two exterior electrodes effective to convert endogenous compounds at the catheter surface to biocidal species. an elongate catheter body comprising a dielectric material having a proximal end, a distal end, a lumen extending through the catheter body and adapted to transport fluid from the proximal end to the distal end, an outer surface on the exterior of the catheter body, and an inner surface on the interior of the lumen; two exterior electrodes (66, 68) on and integral with the outer surface of the catheter, the exterior electrodes being elongate and extending longitudinally along the outer surface of the catheter body from the proximal end to a distal terminus at the distal end and being adapted for applying a voltage across the exterior electrodes of a magnitude that is effective to create a biofilm- inhibiting concentration of oxidizing agents from endogenous compounds present in the body; wherein the electrodes extend radially inward from the outer surface through a wall of the catheter body to the inner surface, thereby additionally serving as interior electrodes; wherein the two exterior electrodes are separated by a pair of gaps (71, 73), each gap comprising the dielectric material of the catheter body, and extending radially from the outer surface to the inner surface of the catheter body and longitudinally from the proximal end to the distal end; and a means for receiving the voltage from a voltage source so that an electric field is generated across the at least two exterior electrodes effective to convert endogenous compounds at the catheter surface to biocidal species.