Simon Cowell has made his decision ... he wants Khloe Kardashian to host "X Factor" and it's now in the hands of FOX -- network sources tell TMZ.

Our sources say Simon made the case that Khloe is a big draw who will complete the circle of making the show decidedly younger than last season. Khloe has a connection to Britney Spears and Demi Lovato and Simon believes the three of them create an authentic vibe that none of the other potential hosts bring to the table.

We're told FOX must now sign off on Simon's choice and that decision is expected within a week.

One source said it's "highly likely" the network will give Khloe its stamp of approval.