Abstract: Steel reinforced filter plates consist of an inner steel sheet and front and back panels composed of thermoplastic resin. The front and back panels of the filter plate are composed of thermoplastic synthetic resin and are bond to each other through a series of prefabricated openings in the steel sheet. The inner steel sheet of the filter plate of the invention further contains at least one exit port hole and a drainage channel leading from the port hole. The filter plate further contains a feed port (passageway) extending from the exterior of the front panel to the back panel. The thermoplastic synthetic resin encompasses all of the exposed surfaces of the filter plate--all of the steel lining the prefabricated openings, port holes and drainage channel being encased by thermoplastic synthetic resin. The filter plate of the invention is produced via an injection molding process wherein a prefabricated steel sheet is first inserted between the upper and lower regions of a mold.