Abstract: A heating pad system comprises a pad formed of layers of flexible material, a heating element applied to or embedded within a layer of the pad and including conductive yarn, a temperature sensor associated with the pad to generate a temperature signal indicative of a temperature of the pad, and a battery-powered control module removably connected to the heating element and the temperature sensor. The control module is operable to supply current to the heating element to generate heat, wherein the current supplied to the heating element is regulated in response to the temperature signal from the temperature sensor to maintain the pad at a substantially constant temperature. The pad layers, heating element, and temperature sensor are machine-washable as a unit. The pad may be worn under an orthopedic or athletic brace.