Harold Camping previously said that Judgment Day would happen on May 21 in the form of an earthquake "beyond the shadow of a doubt", but admitted that he was slightly mistaken.
In a speech broadcast, the American called May 21 an "invisible Judgment Day" and added: "We've always said May 21 was the day, but we didn't understand altogether the spiritual meaning.
"May 21 is the day that Christ came and put the world under judgment."
Camping also mentioned that both the Rapture and the apocalypse will now happen on October 21, and that because Judgment Day happened on Saturday, there was little point warning people about the end of the world.
He stated: "The fact is, there is only one kind of people who will ascend into heaven... If God has saved them, they're going to be caught up."