Director of cricket Dave Houghton is to leave Derbyshire with immediate effect.
Houghton plans to continue his coaching career elsewhere
The former Zimbabwe captain's contract was due to expire at the end of 2007 but the club say they want to start planning for the future now.
"This is an amicable parting of the ways after careful consideration by both David and the club," insisted Derbyshire chairman Don Amott.
Captain Simon Katich and the existing coaching staff will take charge until the end of the current campaign.
"I am obviously disappointed to be leaving because I have thoroughly enjoyed my time here but this is the best way forward for both the club and myself," said 50-year-old Houghton.
His enormous experience has been of great benefit, particularly to the younger players we have coming through our system
Derbyshire chairman Don Amott
"I hope to find another role in cricket before too long and wish Derbyshire every success for the future."
Houghton has been in charge at the County Ground since 2003, following previous spells as coach of Worcestershire and head of Zimbabwe's Cricket Academy.
The team finished second bottom and bottom of Championship Division Two in his first two seasons in charge but last year achieved a respectable improvement to fifth place.
They currently occupy the same place in the table this summer, despite winning only one of their seven games so far, but have under-performed in one-day cricket and failed to win a single one of the four completed matches they played in the Twenty20 Cup
Amott added: "I would like to thank David for his efforts over the past four years.
"His enormous experience has been of great benefit, particularly to the younger players we have coming through our system.
"He has put in a tremendous amount of hard work during his time with Derbyshire and he is to be commended for dramatically improving the ability of our playing squad over the last couple of years and attracting players of real quality to the club.
"We now need to look forward and build on what David has achieved and we will look very carefully at the best way to do that in the coming weeks."