The former Manchester United assistant spent five years at the Riverside – a spell which saw Boro win the 2004 Carling Cup trophy and reach the 2006 UEFA Cup final. The Teessiders also made some terrific signings under McClaren - scroll down and flick through our gallery to see the best of them:
1. (11th) Chris Riggott
Signed from Derby County for around £2million in 2003, Riggott proved to be a valuable player under McClaren. The centre-back was regularly picked alongside Gareth Southgate during Boro's run to the UEFA Cup final and made over 100 appearances for the club before departing in 2010. Photo: Clive Brunskill
2. (10th) Franck Queudrue
The French defender became Boro's first-choice left back after moving to Teesside from Ligue 1 side Lens in 2001. Queudrue also chipped in with a few goals during his five-year stay at the Riverside, netting 12 in total. Photo: Jamie McDonald
3. (9th) Massimo Maccarone
He may not have always been first choice, yet the Italian was always a man for the big occasions. Boro paid a substantial fee of around £8million for the frontman in 2002 but Maccarone more than repaid that fee with his two memorable goals against Basel and Steaua Bucharest in the 2005/06 UEFA Cup run. Photo: AFP
4. (8th) Yakubu
With Mark Viduka and Jimmy Floyd Hasselbaink already at the club in 2005, Boro's attacking firepower was bolstered further when Yakubu was signed for a then club-record fee. The Nigerian international netted 32 during his two years at the Riverside before moving to Everton for £11.25million. Photo: Matthew Lewis