The publisher released some new Before Watchmen preview artwork by Lee Bermejo as part of the launch.
The new site covers the core DCU titles, the Vertigo imprint and MAD Magazine, and features a cleaner look with clearer navigation.
The site also features spotlight pages for its franchises, including Watchmen, Batman and Justice League.
As part of the relaunch, DC has shut down its message boards to be replaced by integrated social media features.
"The new sites are a true representation of DC Entertainment, and the depth and scope of our characters and brands across all media," said Jason James, vice president of interactive marketing for DC Entertainment.
"Our goal is to be the one-stop destination for all fans looking for the latest news on comics, TV, games and movies, and a place where fans can engage with us and each other about all things DC Entertainment. Fans should visit DCComics.com daily - we have a lot of surprises in store for them over the next week and beyond."
> 'Before Watchmen's Amanda Conner draws Silk Spectre - watch video
> 'Before Watchmen' is essential, says DC Comics