"His contract will come to an end by mutual agreement with the Board of Management. Preparations for the forthcoming season continue as planned," Mercedes added.
Haug, who turned 60 last month, has led Mercedes's motorsport division since October 1990 and played a part in signing Britain's 2008 Formula One world champion Lewis Hamilton from McLaren for next season.
He was also a vice-president of Daimler AG.
"He put his stamp on a whole era and, as a highlight, he was responsible for the successful comeback of the Silver Arrows to Formula One," said Daimler CEO Dieter Zetsche.
Mercedes bought the championship winning Brawn GP outfit at the end of 2009 and renamed it as their works team but have had just one win, with Nico Rosberg in China this season, to celebrate since then. (Reporting by Alan Baldwin, editing by Julien Pretot)