Abstract: Multifilament yarn, monofilament, or film, formed at least substantially of polyethylene naphthalate, has a strength of at least 400 mN/tex and a DSC melting point of at least 292.degree. C., where the DSC melting point is measured on a sample quantity of 2.5 mg at a heating rate of 20.degree. C. per min. For production, melted polyethylene naphthalate is extruded from a multi-hole spinneret, the filaments or film, solidified by cooling, are/is withdrawn at a rate of 500 to 10,000 m/min, where the filaments or film are/is subjected to a draw-down B of 40 to 25,000 from the spinneret output to the first withdrawal element. The polymer used may contain at least 85% by weight polyethylene naphthalate and have a melt flow index of 3 to 26.