Ferrari have split with technical director James Allison in what the team say was a "joint decision".
The move comes three years after Allison rejoined Ferrari as part of a restructuring plan to improve the team's performance.
The first car designed under his control won three races in 2015, but Ferrari's revival has stalled this season, with no wins so far.
Mattia Binotto has been promoted to chief technical officer.
His previous role was as head of Formula 1 power-units.
Allison, 48, was also at Ferrari as head of aerodynamics during the dominant Michael Schumacher era of 2000 to 2004, before moving back to the Renault team, where he was deputy technical director when Fernando Alonso won consecutive titles in 2005 and 2006.
He is one of the most highly regarded engineering leaders in F1 and is likely to be of interest to a number of other teams.
He said in a statement issued by Ferrari: "During the years I spent at Ferrari, at two different stages and covering different roles, I could get to know and appreciate the value of the team and of the people, women and men, which are part of it.
"I want to thank them all for the great professional and human experience we shared. I wish everybody a happy future with lots of success."
Ferrari team principal Maurizio Arrivabene said: "The team would like to thank James for his commitment and sacrifice during the time spent together, and wishes him success and serenity for his future endeavours."
Ferrari president Sergio Marchionne has recently been conducting a review of the operational practices of the team, including consulting engineers on all levels, in an attempt to inject more creativity into the team.
This has included a restructuring of the internal workings of departments across Ferrari.
Allison's next destination is yet to be decided but his reputation is such that he would be of interest to most teams.
McLaren were keen to sign him at the start of 2013, but he ultimately turned them down to go back to Ferrari.
And the Enstone-based Renault team, where Allison has worked on three separate occasions, is undergoing a major rebuilding programme following the French company's buy-back of the operation from former owner Genii Capital, which ran it as Lotus from 2012-15.
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