Abstract: A safety retainer for preventing disengagement of a shackle bolt from a U-shaped shackle. The retainer includes a collar member and a pin member. The tubular collar member surrounds the head of the shackle bolt and is provided with a pair of holes through its walls, coaxially alignable with an aperture in the shackle bolt head, and a notch cut out of the wall of one end thereof for engagement with one arm of the shackle. The pin member is insertable through the pair of collar member holes and the shackle bolt aperture to prevent rotation and disengagement of the shackle bolt from the shackle.