A knuckle pin retainer for a railroad car coupler adapted for disposition in an aperture formed by a knuckle coupler assembly for connecting adjacent railroad car. The pin retainer includes a pivot pin with a retaining member installed within the pivot pin. The retaining member extends diametrically from a slot in the elongate shaft and is spring-loaded and rotatable within a slot in the shaft. A spring member is disposed within the slot between a back wall of the slot and the retaining member. The spring member is biased to expose the retaining member outside of the slot.