In 1979, DC and Marvel agreed to co-publish a crossover series involving the two teams, to be written by Gerry Conway and drawn by George Pérez. The plot of the original crossover was a time travel story involving Marvel's Kang the Conqueror and DC's Lord of Time. Writer/editor Roy Thomas was hired to script the book, based on Conway's plot, and although work had begun on the series in 1981 (Pérez had penciled 21 pages by mid-1983) and it was scheduled for publication in May 1983, editorial disputes - reportedly instigated by Marvel Editor-In-Chief Jim Shooter - prevented the story from being completed. The failure of the JLA/Avengers book also caused the cancellation of a planned sequel to the 1982 The Uncanny X-Men and The New Teen Titans crossover.
An agreement was reached between the two companies in 2002, with a new story to be written by Kurt Busiek and drawn by George Pérez. In a joint panel at WonderCon 2000, Busiek (then writer of the Avengers title) and Mark Waid (then writer of the JLA title) stated they had nearly come to an agreement to begin the crossover within the regular issues of the respective titles but the two companies could not come to a business arrangement. When the series was approved, however, Waid was unavailable due to an exclusive commitment with company CrossGen, and Busiek became the sole writer on the project. Perez also had an exclusive commitment with CrossGen, but had a clause written into his contract allowing him to do the series if and when it was approved.
The series was reprinted by DC Comics in 2004 as a two-volume collector's edition hardcover (which included for the first time the original 1983 Pérez penciled pages), and then re-released as a trade paperback in November 2008. As of 2017, it is the most recent crossover between DC and Marvel.