Abstract: A personal, portable heating and cooling system for an individual includes a thin, flexible pad and a control unit in fluid communication with the pad for regulating the temperature of a heat transfer fluid flowing between the pad and the control unit. The pad has an internal chamber for holding the heat transfer fluid. The chamber is partitioned to form therein a passageway that directs the heat transfer fluid to flow there through along a circuitous path. The control unit has a housing enclosing a reservoir for holding the heat transfer fluid, a pump for pumping the heat transfer fluid between the reservoir and the internal chamber of the pad, and a heating and cooling apparatus for regulating the temperature of a heat transfer fluid flowing between the reservoir and the chamber. The control unit includes an electronic control circuit having a user interface that enables a user increase and decrease the temperature of the fluid.