A medical liquid transfer assembly includes a male luer connector (10) and a female luer connector (11), wherein the female luer connector (11) includes a main body having an inner channel (15) for passage of the liquid and a collar (12) surrounding the end of this main body, the male connector comprising a main body having an inner longitudinal opening (19, 21). According to the invention, - the main body of the female connector has on its outer surface a first thread (16) at least partly facing an inner surface of the collar (12), - one end of the main body of the connector Male luer (10) has on a portion of its inner surface delimiting said inner longitudinal opening (19, 21), a second thread (20) intended to cooperate with this first thread (16) to ensure the assembly of the male Luer connectors and female, - at least the outer surface of the male luer connector (10) having the second thread (20) forms a male conical portion (24) and the inner surface of the collar (12) forms a female conical connecting surface (13) of so that this outer surface abuts against the female conical connecting surface (13) of this collar (12) to ensure a tight assembly when assembling male and female Luer connectors.L'invention concerne un ensemble de transfert de liquide à usage médical comportant un connecteur Luer mâle (10) et un connecteur Luer femelle (11), ce connecteur Luer femelle (11) comprenant un corps principal comportant un canal intérieur (15) pour le passage du liquide et un collier (12) entourant l'extrémité de ce corps principal, le connecteur mâle comprenant un corps principal comportant une ouverture longitudinale intérieure (19, 21). Selon l'invention, - le corps principal du connecteur femelle comporte sur sa surface externe un premier filetage (16) placé au moins en partie en regard d'une surface intérieure du collier (12), - une des extrémités du corps principal du connecteur Luer mâle (10) comporte sur une partie de sa surface interne délimitant ladite ouvertu
