The move paves the way for the hunting of wolves in the US for the first time in more than 30 years.
The Fish and Wildlife Service said the Mid-West states of Michigan, Minnesota and Wisconsin would be removed from the list within weeks.
The states of Idaho, Montana and Wyoming could be removed in a year.
Wolves were hunted to near-extinction in the US before being classified as endangered in 1974.
In the 1970s, conservationists seized the chance to save the animal with recovery programmes in several states, involving restoring habitat and prey species, and compensating ranchers for livestock killed by wolves.
The wolf has responded so well to conservation programmes that it will now be legal to hunt them again.