With the club sitting in the Premier League drop zone, Aitor Karanka has been relinquished of his duties at Middlesbrough.
Ahead of facing Manchester United on Sunday afternoon, the north-eastern side have lost six and drawn four of their league games since their 3-0 win over Swansea in late December, dropping them to 19th.
"Middlesbrough Football Club can today confirm the departure of Head Coach Aitor Karanka," read an official statement.
"Following discussions, both parties have agreed that it is in the best interests of the club to make this change.
"The club would like to thank Aitor for all his hard work over the past three-and-a-half years and for the success we've had during that time. We wish him all the best for the future.
"Assistant coach Steve Agnew has been moved into the hotseat for the time being, leaving Karanka to send his best wishes to Boro after three-and-a-half years at the Riverside Stadium.
"I'd like to thank Middlesbrough for a wonderful opportunity and the players, staff and all the people at the club who I have worked with," he stated.
"I'd also like to thank the fans for their support. This club will always hold a special place for me and I wish everyone connected with Middlesbrough Football Club the very best for the future."
