Martin O'Neill parted company with Sunderland on Saturday night after the Black Cats slipped deeper into relegation trouble.
The 61-year-old's departure was confirmed hours after the 1-0 home defeat by Manchester United, which left the club sitting just a point clear of the Barclays Premier League relegation zone with seven games left to play.
A club statement said: "Sunderland AFC has announced that it has parted company with manager Martin O'Neill this evening. The club would like to place on record its thanks to Martin and wishes him well for the future. An announcement will be made in the coming days regarding a successor."