Urban Dead is an HTML/text-based massively multiplayer online role-playing game created by Kevan Davis. Set in a quarantined region of the fictional city of Malton, it deals with the aftermath of a zombie outbreak. Players enter the game either as a human survivor or a zombie, each with different abilities and limitations. Humans become zombies when they are killed, while zombies can be "revivified" with appropriate technology, becoming human. There are no non-player characters in the game: all humans and zombies are controlled by players.

Gameplay involves zombies breaking into safe houses and attacking the inhabitants, and humans trying to defend the buildings by barricading them and killing any zombies present. Safe houses tend to be located in or near buildings where useful items can be found, such as shopping malls, police stations, hospitals, and the laboratories of the zombie-related NecroTech corporation.[1] Cooperation between players isn`t strictly enforced. Internal fighting between survivors and zombies is a frequent occurrence.[1] Urban Dead has no economy. Human characters can loot supplies from abandoned buildings indefinitely, but cannot trade, sell, or give them to other players. New players begin the game as one of the three survivor classes; Military, Science or Civilian; or as a Zombie. Each side in the struggle has its own advantages and disadvantages. Humans move twice as fast as low-level zombies and are able to employ various weapons and tools. Human characters can communicate with each other in-game via speech, radio broadcasting, and text messaging. They can also barricade building entrances, keeping zombies at bay. Zombies, often referred to as "zeds" or "zack", are limited to using claws, teeth, and blunt melee weapons. However, they are able to stand up again when killed, at the cost of several action points, rendering them effectively immortal. Higher level zombies can communicate with each other via a crude form of zombie speech, as well as through groaning noises and hand gestures. It is possible to switch sides in the conflict: a human character that is killed will rise up as a zombie, and zombie characters may be re-animated as living humans by a survivor who has the relevant skills and items.

Humans who die and return as zombies do not have to switch sides. Zombies that were once humans can gather at designated "revive points" scattered through out the city where they wait for humans with the relevant skills and equipment to revive them. Revive points are considered neutral ground and survivors are generally discouraged from killing zombies found there. Some players and groups on both sides have also set their own distinct goals, many of which are set for purely role-playing purposes. Urban Dead is not limited to survivor versus zombie combat, groups of survivors can attack other survivors, known as player killing. Within the game, this is viewed as an act of murder; however, it is not against the game rules and is seen by some more advanced players as playing the game on "Hard" due to only receiving half the experience points that one would receive for attacking zombies. Individuals that engage in this behavior are often tracked by bounty hunters. Some zombie groups utilize human characters as spies and saboteurs, usually during or in preparation for a major attack on a safe house (mainly malls). These collaborators are often referred to as "zombie spies" or "death cultists". On the other hand, zombies desperate for experience points or health may turn on and attack their own kind (known as ZKing in-game), again similar to PKing; however, this only generates half the usual experience points. Many survivors turned zombies, believing their allegiance is "to the human race", will still zombie kill until revived.

Urban Dead was created by Kevan Davis, a freelance video game designer and web developer, in 2005. Davis was inspired by a similar game called Vampires!, which was created by a friend, and play-by-mail games. These were combined with elements of NetHack, MUSHes, interactive fiction and a zombie infection simulation he had developed in 2003. This created a game which required approximately 10 minutes of planning and play a day; involving exploration, interaction and item discovery.

As of March 19, 2009, there was a total of 1,492,351 registered characters with 26,472 active. In Monroeville, the version of Urban Dead where death is permanent, there is a total of 169 active characters. 7 being survivors and 162 being zombies.