The 23-year-old prop or back rower made nine appearances for the Robins in 2015, but struggled to seal a first-team spot.
“Since I came into the club, I have been impressed with Jordan and how he has handled this situation. His behaviour has been impeccable and he moves to Warrington on good terms with everybody at Hull KR.
“From our point of view, we’re looking to further improve the squad for next season and we have identified areas where we would like to strengthen.
“We are exploring all of our options but any new player must fit into our philosophy both on and off the field.
“We have a long-term plan in place in terms of recruitment and we are only interested in players who fit into this strategy.”
Warrington head of coaching and rugby Tony Smith is pleased to have reinforced his forward pack for the 2016 season.
“We are delighted to have signed Jordan,” he said.
“He is a big human being and fits the brief of what we are after here. He will add more depth to our forward pack and create more competition for places both in the middle at prop and back row positions.
“He’s been a former representative in the England Knights set-up and he has ambitions to go some steps further and we will be trying to help achieve some of those.”
Cox himself is looking forward to beginning a new stage of his career at Wire.
“It’s a massive club. Warrington are always near the top, always there or thereabouts, pushing for silverware and challenging for top spot,” he said.
“I want to be a part of that. Warrington is a side I can hopefully push on in. The facilities here were a massive factor when I got shown around. What you put in and invest in off the field, you get back on the field.
“The indoor training facility and gym here are top notch and it’s working on the field too. I have fitted in really well so far.
“I know a couple of the lads already but it’s been good to meet all the players, staff and conditioners, everybody has been really good with me.”