The present invention provides a male luer connector for sealing a female luer connector, said male luer connector comprising a base portion adapted to removably connect with the female luer connector a protruding portion adapted to be inserted into the female luer connector a through hole extending through the protruding portion and the base portion and adapted to receive a needle and a valve device arranged in said base portion and adapted to block fluid flowing in said through hole in the direction from the female luer connector via the protruding portion out of the male luer connector when the male luer connector is connected to the female luer connector. The present invention also provides a catheter hub comprising such a male luer connector as well as a method of inserting a catheter in the vascular system of a patient.
