Shortwave diathermy (SWD) is a therapeutic modality that uses electromagnetic energy to generate deep heat in tissues. It can be delivered continuously or pulsed. The frequency used, type of SWD unit, and water content of tissues affect the pattern of heat produced. SWD has various therapeutic effects like increasing blood flow and accelerating wound healing. It is used to treat conditions like recent injuries, arthritis, and muscle pain and spasm. Proper application of SWD involves preparing the patient, machine, and electrodes to deliver controlled doses of energy to target tissues while avoiding risks like burns or electric shock.