A temperature control unit for dies and molds, particularly for pressure die-casting or injection-molding of aluminum and alloys thereof, plastic materials and the like, comprising a die or mold cooling circuit through which pressurized water flows. A water feed pump is connected to the circuit and is adjustable to a pressure which is higher than the evaporation pressure of water at a preheating temperature of the water, which can be detected by a first sensor for detecting the temperature of the water. The circuit includes a circulation pump, a water overflow valve which can be set to a lower pressure than the feed pump, and a heating unit which is controlled by the first temperature sensor. A die or mold temperature sensor is further provided which controls the feed pump.