Abstract: A separable catheter needle for inserting a flexible vessel catheter into a blood vessel is adapted to be separated after taking a blood sample and comprises a needle tube of metallic material with a gripping and catheter inserting portion consisting of several elements made preferably of thermoplastic material. The needle tube consists of two tube halves which are assembled and bonded together along their meeting edge. An elastic or plastic sealing element is introduced into the assembled needle tube so that it engages its inner wall to provide a sealing of the tube against air and liquid. The rearward end of the needle tube has integral wing members which are covered by a gripping plate device consisting of a grooved central portion and of two lateral plate elements which fit over the tube and its wing members. The lateral plate elements cooperate with the wing elements to provide a mutual interconnection.