Abstract: A toggle bolt assembly has a solid toggle head which is threadedly mounted on a cylindrical helical coil spring coaxially attached to the end of a threaded bolt, the coils of the spring having an outer diameter and a pitch which correspond substantially to those of the threads of the bolt, so that the spring forms a flexible extension of the threads of the bolt. With the toggle head mounted on the spring near the free end thereof, the spring can easily be bent to position the toggle head adjacent the bolt and substantially parallel thereto, thus permitting the entire assembly to be passed through an opening in the member in which it is to be installed. As soon as the toggle head has passed entirely through the hole, the resiliency of the spring causes it to straighten out, thus positioning the toggle head across the opening on the blind side of the hole.