Manager Neville Powell has been "relieved of his duties" after nine years in charge of Bangor City.
A club statement gave no reason for the move, but said it came after a "difficult pre-season build up".
Under Powell's guidance, Bangor won the Welsh Cup for three consecutive seasons between 2008 and 2010, and won the Welsh Premier League in 2010-11.
Bangor finished ninth last season and were taken over by a Cheshire-based consortium in June 2016.
The club will hold a testimonial match for Powell before the end of the 2016-17 season.