J Michael Straczynski and Chris Weston's long-awaited comics will be released early in 2012.
Weston recently revealed that he had completed work on the outstanding issues #9, #10, #11 and #12.
Marvel's senior vice president/executive editor Tom Brevoort said: "It's taken a long while, but finally, FINALLY, the balance of The Twelve has been completed and we're ready to ship it all to our long-suffering fans.
"We appreciate everybody's patience, and both hope and expect that the conclusion will live up to the wait. And for folks who missed out the first time, we're making it easy to get back on board no matter how much or how little of the previous eight issues you may have already read."
Marvel will release a trade paperback collection of the first six issues in January and a 'Must Have' issue collecting #7 and #8 in February.
The Twelve #9 and #10 are scheduled for release in February, with #11 coming in March and the concluding #12 in April.
The Twelve features 12 little-known characters from Timely Comics, an earlier incarnation of Marvel. The characters must learn how to make their way in a strange world when they are transported into the present.
Straczynski was recently named among writers who are being considered for a series of Watchmen prequels.