Craig Hignett has left his job as Hartlepool United manager by mutual consent following Saturday's 1-0 League Two defeat by Crawley Town.
Hignett, 47, was appointed in February 2016, taking over from Ronnie Moore in his first managerial post.
However, the former Middlesbrough and Barnsley midfielder was unable to turn around Pools fortunes, winning only 14 of 46 league games in charge.
Pools are currently 19th in the fourth tier, four points off the bottom two.
"I would like to place on record my thanks to Craig for all of his efforts," chairman Gary Coxall told the club website.
"He has given everything for the club during his time in charge and he leaves with our very best wishes for the future.
"The search for a new manager will begin immediately and it won't be a long, drawn-out process - we want to get the right man appointed as quickly as possible."
Sam Collins will take charge of first-team affairs until a successor is appointed.
This exit makes him the 10th different manager Pools have employed since Danny Wilson left his post in December 2008.
Hignett was a popular choice as manager to replace Ronnie Moore at Victoria Park, having previously enjoyed a successful stint as assistant to Colin Cooper.
That partnership helped Cooper win a manager of the month award in October 2013, and took the club to ninth in the division, before Hignett left to join Aitor Karanka's coaching staff at Middlesbrough in March 2014.
His return to Pools last season began well, steering the club away from danger with a seven game unbeaten run through to March 2016.
After a reasonable start for Pools this campaign which saw them lose just two of the opening 12 games, form has slipped and only two teams - Cheltenham and Newport have failed to win fewer games.