DR Sally Irvine, chairman of Colchester Hospitals Trust, is to step down later this year.
The trust, which runs Colchester General Hospital and Essex County Hospital, was placed in special measures last November following allegations staff had been bullied into changing patient records to hide missed cancer targets.
Dr Irvine, who has been chairman since August 2010, said now was the right time to announce plans to leave.
She said: “Now that the new Council of Governors is in place and the Trust’s Care Quality Commission hospital inspection has taken place earlier this month, I feel it is the right time to announce my intended departure as Chair of the Trust Board.
“Late last year our Trust was placed into special measures, partly because of governance breaches relating to cancer services. Since then the Trust board has been working hard to develop and implement a number of action plans designed to ensure that every one of our patients receives good quality care.
“An assurance review conducted by NHS England earlier this year indicated that the Trust is making progress against these action plans.
"It recognised that there have been a number of improvements, particularly that members of staff are more confident and engaged compared with a year ago, and that patients and visitors the NHS England review team spoke to were very complimentary about the care and treatment they received.
“Much remains to be done and we cannot be complacent about the size of the task ahead but I feel that with help, we have identified the issues to be addressed and we have turned the corner.
"This is therefore the right time for me to make this announcement."
For more, see Tuesday's Gazette