Red Dead Redemption: Undead Nightmare is the fifth downloadable content (DLC) pack released for Red Dead Redemption. It was released for the PlayStation 3 and for Xbox 360 on 26 October 2010. Undead Nightmare follows the exploits of John Marston, as he looks to find a cure for an infectious zombie plague that has swept across the American Old West.
A standalone disc titled Red Dead Redemption: Undead Nightmare Collection which does not require the original Red Dead Redemption game to be played, was released on 22 November in North America and 26 November in Europe. The disc includes three DLC packs: Legends and Killers, Liars and Cheats & Undead Nightmare Pack.