Care Quality Commission chief executive Ian Trenholm will step down at the end of this week after a six-year spell leading the regulator.
Kate Terroni, the CQC's deputy chief exec will become interim chief executive while the organisation, which is a non-departmental public body overseen by the Department of Health and Social Care, searches for a permanent replacement.
Trenholm explained that he had decided to depart now having delivered on the organisation’s "complex" transformation ambitions.
"During my six years leading CQC, we have made important changes to the way we work in order to help improve care and keep people safe,” he said. “We are now in the final stages of delivering an ambitious transformation programme – this month saw the delivery of the last big milestone in a complex and challenging programme of work.
“While there will always be more work to do, the conclusion of this stage of the transformation feels like a good time to move on. It has been a privilege to work with such a passionate, committed and talented group of colleagues.
"I am incredibly proud of what we have achieved together, and I am confident that the organisation will continue to evolve to help support the health and care system to provide good, safe care for people."
CQC chair Ian Dilks said Trenholm had led the organisation towards its ambition of being a “smarter and better regulator” and expressed the board’s thanks to him for his contribution to the CQC.
"The board would like to thank Ian for his contribution to CQC over many years and for leading us towards our ambition of being a smarter and better regulator," he said.
"I and my board colleagues look forward to supporting and working with Kate in the further development of CQC."
Trenholm's departure comes after a CQC staff survey earlier this year found just 27% of employees felt the “values and behaviours” of the chief exec and executive team matched those of the organisation, down from 55% three years ago.
Before working at the CQC, Trenholm was chief operating officer at the Department for Environment, Food and Rural Affairs.