Cambridge United have parted company with manager Richard Money with the club 18th in League Two and having won just five league games this season.
Money, 60, was appointed three years ago and led the U's to promotion back to the Football League in 2014, winning the FA Trophy in the same season.
Cambridge reached the fourth round of the FA Cup last season and earned a replay against Manchester United.
Assistant manager Joe Dunne will be in charge until a new boss is found.
Money is set to make a statement on his departure through the League Managers' Association later on Monday, while Cambridge's chairman Dave Doggett and chief executive Jez George will hold a press conference on Tuesday.
|Money's Cambridge record|
|U's win FA Trophy at Wembley in March 2014|
|Two months later, leads club back to the Football League after nine years in the Conference|
|Finish 19th in League Two last season, winning 13 of 46 matches|
|Hold Manchester United to a 0-0 draw at the Abbey Stadium in the FA Cup in January before losing 3-0 in the replay at Old Trafford|
|Won 67 and lost 58 of his 170 games in charge|
"The club has taken this difficult decision due to the disappointing pattern of results over the last nine months and because the current squad is not showing consistent signs of achieving its potential," said a statement on the club website.
"We want to place on record our sincere thanks to Richard, who has been instrumental in the club's progress over the last three years.
"Richard has achieved a special place in the history of Cambridge United Football Club and will always be warmly welcomed at the Abbey Stadium."
Money signed a new three-year contract in May, when his job title was changed from head coach to football manager, reflecting a wider responsibility for player recruitment, formerly handled by chief executive Jez George.
Analysis: BBC Radio Cambridgeshire's Mark Johnson
"I was expecting this at some point, but not at this immediate juncture.
"You could look at perhaps a number of injuries he had this season, but it goes much deeper than that.
"If you go back to January, just after they played the Manchester United games - since then they've had 41 matches and just eight wins.
"I think that really does tell the story of decline that needed to be stopped and it needed drastic action to stop it."