Josh Gowling left the National League North club following Boxing Day’s 2-0 loss to Scarborough Athletic.
That came after Saturday’s defeat at basement boys Bishop’s Stortford and they club are now eight points from safety with one win in seven.
The Quakers sit second bottom of the table and have won just four games all season, fewer than anyone else in the division.
Former Hereford manager Gowling took charge in September but has been unable to transform the club’s fortunes since they parted company with Alun Armstrong
The Darlo board will know a quick appointment is important with no time to lose in the race to avoid the drop with games coming thick and fast. They face the Seadogs again on Saturday before trips to King’s Lynn and Southport.
“Following our 2-0 defeat at Scarborough today, Darlington FC have regrettably parted company with manager Josh Gowling,” the club confirmed in a statement.
“We would like to thank Josh for all his efforts since he was appointed in September. We will make an announcement about the ongoing position in due course.”