Abstract: A injection molding nozzle with an automatic shut-off valve is disclosed. The present invention is intended for use with injection molding machines employing a screw plasticizer and an injection plunger. The nozzle, as a conversion unit, fits any in-line screw injection machine. The nozzle can, also, be employed as part of a two-stage injection molding machine capable of injection molding, conventional, semi-foam or structural foam. The nozzle of the present invention has smooth flow passages and a few parts which are of simple construction allowing the nozzle to be easily cleaned for conversion to different materials.