Aalborg have parted company with coach Bruce Rioch with immediate effect, the club announced on Thursday.
The Danish side have failed to emulate last season's success when they won the league title and qualified for the Champions League for the first time in their history.
Instead AaB are second from bottom in the domestic standings with two wins from 10 matches and also prop up Champions League Group E with a single point behind Celtic, Villarreal and Manchester United.
Former Arsenal and Bolton manager Rioch was told earlier this month his contract would not be renewed when it ended on December 31.
But a 2-1 home defeat to FC Nordsjaelland last weekend proved the final straw for AaB and their director of sport, Lynge Jakobsen, who suggested a difference of opinion was behind Rioch's immediate departure.
"Qualification for the Champions League was a success, but we have to say that our results in SAS Ligaen have not been satisfactory,'' Jakobsen told the club's official website.
"We have decided to stop now because we are no longer in agreement with Bruce Rioch about what is the best way to get satisfactory results in the coming weeks.''
Assistant coach Allan Kuhn will take charge of the team for the rest of the year.