The Chelsea youngster returned from World Cup duty with Nigeria this week and impressed the Middlesbrough boss during his four appearances in Brazil.
"I like Kenneth not because of what he has done at the World Cup, I like him because he's a very good guy and very good player," Karanka said.
Omeruo made 14 appearances for Middlesbrough last season and Karanka would like to see the defender return to the Riverside Stadium.
"He played those games in a very good way. I was in contact with him during the World Cup, he wants to join us, Chelsea want to send us the player on loan and we would like to have him back with us again.”
Meanwhile Karanka has not given up on signing Real Betis right-back Juanfran, who is mulling over a potential move to the north-east.
Karanka confirmed the player is weighing up his options and told the Gazette: “The first thing that I want from the players who join us is that they want to join us.
"First and foremost, the most important thing is that the players want to be with us - after that everything is easier.
“At the moment he is thinking about the possibility of coming here but we are also working on other players. It’s in his hands.
"I think it is difficult because he is looking at other offers in Spain and for this reason we can’t stop and wait for him, we have to look for other players.”