Hearts lost 3-0 to Aberdeen at home in midweek and are currently fifth in the Scottish Premier League.
Laszlo won the Manager of the Year award in his first season in charge in 2008.
“Hearts announce the departure of Csaba Laszlo from the club with immediate effect,” read a statement on the club’s official website.
“The club has begun the search for his replacement and hopes to make the new appointment at the earliest opportunity.”
