Jimmy Tolan is to step down as Chief Executive of the VHI.
Mr Tolan told the board that he intended to return to the private sector, a statement from the health insurer said.
He became chief executive in 2008 and previously headed fruit importing company Fyffes.
VHI said his contract required him to give the board six months' notice.
VHI chairman Bernard Collins said Mr Tolan's resignation had been accepted 'with regret' and described him as an 'outstanding CEO'.
Minister for Health James Reilly said that Mr Tolan may have had issues with some of the options for the company under consideration by the Government.
The minister met with Mr Tolan in the Dáil yesterday and said he could not support a break-up of the VHI.
The minister has commissioned a report from consultants Goodbody, which involves a review of the VHI in the context of how the proposed Universal Health Insurance system can be introduced.
