A medical catheter tube containing a tetrafluoroethylene polymer, which has a wall thickness of 0.1mm or below and exhibits a tensile strength (S1) at 1.0 mm displacement of 5.0N/mm 2 or above; and a process for the production of medical catheter tubes, characterized by molding a composition comprising both a tetrafluoroethylene polymer and a lubricant having high affinity for the polymer by paste extrusion. The invention provides thin-wall medical catheter tubes excellent in elongation resistance, kink resistance and internal cavity lubricity.