Phase controlled optical thin films on solid cube corner retroreflectors have been shown to successfully maintain the
polarization state of the incident light. This paper considers the theoretical basis for this effect when only two of the
three total internal reflecting faces of the cube corner have coatings with zero phase retardation and when the incident light is monochromatic and S or P polarized. Such polarization preserving retroreflectors are highly useful and are integral components in advanced heterodyne displacement measuring interferometer systems.