A ladder safety support for use with an existing ladder is disclosed. The support includes an attachment assembly for removable connection to the lower end of the ladder and one of two interchangeable foot assemblies for supporting the ladder on a surface. The first foot assembly provides a surface-penetrating stake having a lower tapered section and presenting a pointed tip and a threaded portion for removably attaching the stake to the assembly. The second foot assembly is similarly removable and provides a surface-engaging pad.