It is the latest twist in a saga which began back in June when the former Australian Test player Dean Jones quit as captain and overseas professional.
Speculation about Horton's position at the club he saved from financial ruin in 1993 increased when, after returning from a business trip abroad, he stayed away from the Championship match against Lancashire at Derby on Saturday.
He announced his resignation through a letter to the Derbyshire members in which he was critical of the committee and suggested a restructuring of the club.
Horton's proposals include turning Derbyshire into a limited company and replacing the committee structure with an elected management board.
"I have found it increasingly frustrating that my efforts in all of these directions have been consistently undermined by certain members of the committee, especially during my absences from the club," Horton said.
"The peripheral issues that occur during the season, especially recently, give an opportunity for individuals to hide their fundamental motives."
Vic Brownett, the vice-chairman who has been in charge during Horton's absence, will now take over until a new chairman is appointed. "This is a sad way to go," Brownett admitted. "Mike has done a tremendous job for Derbyshire and I have learned a lot from him."Reuse content