Abstract: A protective device for injection or aspiration needles has a barrel piece telescopically slidable over an adapter sleeve mounted at one end to the luer coupling of the syringe or to a multisample collector. An injection needle is mounted within the adapter sleeve, projecting out through an opening in the opposite nose end of the barrel piece. An interposed spring urges the adapter sleeve and barrel piece apart towards a fully extended position. The barrel piece and adapter sleeve are latched together in a ready to use position with the needle partially protruding out from the barrel piece. As the syringe or multisampling system is advanced, the needle is extended out through the barrel piece end to allow penetration into the patient's body, and automatic unlatching is induced as penetration begins.