Abstract: An apparatus for treating patients using electrical interferential therapy is disclosed. The apparatus uses multiple electrodes to define multiple treatment channels, with each channel having a discrete frequency and an adjustable beat frequency between all or selected channel pairs. This adjustment can be done between treatment sessions or can be done during the treatment session by the technician or by the apparatus as programmed. The multiple treatment channels can be used on the same patient, or can be used by the same or a different technician to treat additional patient(s).