A medical connector, preferably a sampling connector for use as an adaptor for a three-way tap arterial blood sampling device, comprises a one-way valve 118 fitted directly into an end of a stop valve 116 such that a fluid tight seal is provided therebetween. The valve arrangement 116, 118 being disposed in a connector body 112, 114 which may be formed in one piece with a folding, snap fit closure (312, Fig 25). The stop valve 116 serving to prevent fluid flowing out of the end 111 of the connector body 112, 114 unless a complementary end of a separate device, typically a Luer connector, engages it. To facilitate manufacture and assembly, the valve arrangement 116, 118 may further be formed from a single piece of elastomeric material, the parts being hingedly connected so that the one-way valve 118 can be folded and fitted directly into the end of the stop valve 116.
