Roger Carr has been chairman at Cadbury for two years
The three men at the top of Cadbury have all announced their resignations following Kraft Foods' takeover of the chocolate maker.
Chairman Roger Carr, chief executive Todd Stitzer and chief financial officer Andrew Bonfield are all to step down, Cadbury said.
US firm Kraft sealed its takeover on Tuesday after Cadbury shareholders voted in favour of the deal.
For months, Cadbury had rejected a hostile bid from Kraft.
In January, the board approved an increased bid of £11.5bn ($18.9bn) and advised shareholders to accept it, saying it offered "good value".
Mr Stitzer, who has been with the company for 27 years, said: "I wish [Kraft chief executive] Irene Rosenfeld and her team every success in taking Cadbury and its brands forward.
"I will now be taking some time out with my family to consider my future options, but you can be sure my heart will always be a deep Cadbury purple."
Mr Stitzer, who became chief executive in 2003, is expected to leave with a package that could be worth up to £20m.
Mr Carr said: "Together we have fought an excellent defence campaign and delivered substantial value to Cadbury shareholders.
"In handing over to Irene Rosenfeld I wish her the very best as she takes on responsibility for continuing to build and develop what is indisputably one of the world's greatest brands."
The dates when all three will officially leave the company have yet to be decided.