Essex head coach Paul Grayson has left the county by mutual consent after eight years in charge.
He was promoted from second-team coach in July 2007 and guided them to Friends Provident Trophy victory in 2008.
Essex have since failed to win any silverware, and are sixth in County Championship Division Two with four games left to play this season.
|Analysis: BBC Essex's Glenn Speller|
|"Coming just 24 hours after the departure of bowler Reece Topley to Hampshire, it is clear there are big changes ahead at Essex. The club is in danger of stagnating in Division Two and the heady days of the 1980s and early 90s are clearly no more than ancient history. "Paul Grayson has been a loyal player and coach but after a number of internal appointments it is, in my view, imperative the club looks outside for a replacement and a fresh approach."|
Assistant head coach Chris Silverwood, a former England pace bowler, will take temporary charge until the end of the season.
"I have had 19 wonderful years at Essex, both as a player and as a coach, but I now feel the time is right for a new challenge," Grayson told the club website.
"I have always been a strong supporter of the club's policy of developing our own players into first-class cricketers and it is a pleasure to see so many doing well in the game.
"I would like to thank the players for their hard work and dedication, particularly the three captains I have worked with; Mark Pettini, James Foster and Ryan ten Doeschate."
|Grayson's international pedigree|
|Paul Grayson made two one-day appearances for England - both on the 10 October. His made his debut against South Africa in 2000 and played his second game against Zimbabwe in 2001.|