Abstract: A system for preventing needle stick or re-use of unsterile hypodermic needles or the like. The hypodermic syringe includes a spring biased, locking push button apparatus exterior to the plunger, which communicates with a locking safety sheath situated at the base of the hypodermic needle prior to activation. The safety sheath is in sliding, longitudinal communication about the needle and is activated to its sheathing position by urging a push button on the locking push button structure in the direction of the needle, directing the sheath from about the base of the needle to over the tip of the needle. Upon communication with the tip, the safety sheath deploys a locking hatch, preventing the urging of the sheath back to the base, and rendering the needle un-reusable.