The 21-year-old is expected to move to Teesside for the duration of the season after seeing his path to the Gunners' first team blocked by the arrival of Germany international Shkodran Mustafi.
Boro had hoped to sign Chambers on a long-term deal but Arsene Wenger was unwilling to let the young prospect leave Arsenal permanently, after parting with £16 million to prise him from Southampton two years ago.
Youngster brings top-level experience
With three senior England caps, more than 50 Premier League appearances and a number of outings in the Champions League, Chambers will bring experience to Boro's back line despite his tender years.
As a product of the famed Southampton youth academy which has produced players such as Gareth Bale, Alex Oxlade-Chamberlain and Theo Walcott, Aitor Karanka will expect Chambers to arrive as a polished defensive player.
Since making his Premier League debut as a teenager and making the move to Arsenal, Chambers has played in the right and centre of defence as well as in midfield.
This versatility should see him fare well at the Riverside Stadium, where Chelsea defender Tomas Kalas has previously found success in a number of positions while playing on loan from his parent club. Kalas is now on loan again with Fulham.
Chambers still has Gunners future
Should he perform well for Karanka's side, the Spaniard may well attempt to sign Chambers permanently once again at the end of the season, provided they match their goal of avoiding relegation back to the Championship.
However, he may well still have a long-term future in North London, so Arsene Wenger is likely to keep an eye on his development over the course of the season.