The debut of "The Late Show with Stephen Colbert" on CBS was watched by 6.6 million viewers, easily outpacing its late-night competition, according to Nielsen figures cited by the network.
CBS said the "Late Show" was up 131% compared with last year's season opener, when David Letterman was hosting the program.
Its viewership total was more than double the audience of 2.9 million that watched NBC's "Tonight Show with Jimmy Fallon."
ABC's " Jimmy Kimmel" averaged 1.8 million viewers.
Prior to Mr. Colbert's arrival, "Tonight Show" had averaged 3.3 million viewers this summer while "Jimmy Kimmel" was drawing 2.2 million viewers.
A big audience for Mr. Colbert's CBS premiere was to be expected.
He had a very loyal audience from his previous show, "The Colbert Report" on Comedy Central, and CBS Corp. also heavily promoted the launch.