Dr Tony Holohan will retire from his €187,000 a year job as Chief Medical Officer today.
He's held the position for the past 14 years, and came into the spotlight during the Covid pandemic.
He will be replaced by Professor Breda Smyth on a temporary basis while the role is filled permanently.
The job was advertised on publicjobs.ie for a number of weeks with the salary worth around €180,000 a year.
Dr Holohan was due to begin a secondment at Trinity College Dublin today, but that was abandoned following controversies around the appointment.