The Undead Nightmare downloadable content pack has launched on PlayStation 3 and Xbox 360 and sees outlaw protagonist John Marston take on his toughest challenge yet - surviving a deadly zombie plague.
Gamers can expect to take on a variety of undead beasts, zombie animals and mythical creatures, while getting to grips with an all-new weapon, the blunderbuss.
The pack also introduces new multiplayer options, including the Undead Overrun survival mode, which challenges players to team up in order to fend off increasingly punishing waves of zombie horrors.
Sam Houser, founder of developer Rockstar Games, said: "The supernatural vibe and the return of some favourite characters create a whole new game inside an already incredible world."
Red Dead Redemption scored one of the biggest launches of the year when it made its debut in May 2010 and remains one of the year's most popular titles.