A passive needle guard includes a body having a cavity therein for receiving a syringe, and a shield. The body is slidable with respect to the shield between retracted and extended positions covering and exposing, respectively, a needle extending from the syringe, the body being biased towards the retracted position. Latch members extend from the shield that include catches for engaging mating catches on the body for holding the body in the extended position. During use, the needle extending from the syringe is inserted into a patient. A plunger is depressed to inject medication from the syringe, thereby deflecting the latch members to disengage the catches and release the body, whereupon the user may controllably retract the body to the retracted position. In the retracted position, cooperating detents on the shield and body engage one another, thereby substantially permanently covering the needle with the shield.