The companies said this is a clear sign that YouTube's deals with TV and traditional media could be paying off.
CBS said ratings of its late-night programs have seen increases since uploading the shows, including adding 5 percent or 200,000 new viewers to "Letterman" and adding 7 percent or 100,000 viewers to "The Late Late Show with Craig Ferguson."
"Although the success of these shows on YouTube is not the sole cause of the rise in television ratings, both companies believe that YouTube has brought a significant new audience of viewers to each broadcast," the companies said.