The present invention relates to a single use safety syringe (100) with a spring actuated needle cover to prevent needle stick injury and auto disabling of the syringe by locking of the plunger to the syringe to prevent reuse. The single use safety syringe (100) according to the present invention comprises a body (14), a plunger (29) a sheath (7) and a spring (10). At the end of the injection stroke, the spring (10) actuates the sheath (7) which glides over the body (14) to cover a needle (2) attached to the body (14). Further pressing the plunger (29) locks the plunger (29) into the body (14) thereby rendering the syringe non-reusable.
