Abstract: A safety retractable sheath covers an injection needle for protection against accidental pricking. The sheath extends from a base secured to the hub of the needle and has bellowed walls made of resilient material. It may be axially retracted toward the hub to expose the needle, and springs back to cover its entire length when released. A constricted section of the sheath beyond the tip of the needle is axially offset to prevent accidental exposure of the tip. A latching bellow segment surrounding the base allows for adjustment of the sheaths to the lengths of the needle.