Abstract: A plastic injection machine nozzle heater housing and heater. The heater housing includes a heater body having an axial thru-bore for receiving a plastic injection machine nozzle of interest. Bores may extend into the heater body from a rear face thereof for receiving corresponding cartridge heater(s) and a thermocouple. A wire receiving groove may be provided to hold the cartridge heater and thermocouple wires. A wire passage aperture may be provided to permit the cartridge heater and thermocouple wires to extend from the heater body for appropriate connection to a heater controller or other appropriate device. Cartridge heater(s) and a thermocouple are inserted into the corresponding bores and a cover plate of the heater housing is then secured to the end of the heater body so as to cover the heater(s), the thermocouple, and the portion of the associated wires residing in the wire receiving groove.