Ellis, 27, played 17 Super League games in 2016, scoring five tries.
He told the club website: "It's going to be a competitive season, but hopefully we should do really well and I'm looking to help Hull KR get back up to where they belong."
Meanwhile, Albert Kelly, Mitch Allgood, Kevin Larroyer, Josh Mantellato and John Boudebza have all been released.
Relegated Hull KR have signed Huddersfield Giants half-back Jamie Ellis on a season-long loan deal.