The game's mechanic is the d20 System published by Wizards of the Coast with character classes and races specific to the setting.

Characters have a low number of hit points meaning that they can die very easily, in keeping with the show.

A second edition of the core rules was published in 2006 using the WotC Open Game License.

[2] In 2008 Mongoose published Universe of Babylon 5, a set of rules allowing the game to use Mongoose's edition of Traveller as its RPG engine instead of the d20 System.

Babylon 5 won the 2004 Silver Ennie Award for "Best Licensed Product".