Dr Tony Holohan will retire from his 187,000-euro-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 was due to begin a secondment at Trinity College Dublin today, but that was abandoned and he's stepping down as CMO completely.
Junior Health Minister, Frank Feighan, says he showed great leadership during the pandemic.
He was able to inform and also TO show huge leadership ability.
People trusted him and people trusted his knowledge, but also trusted his evidence base, and the way he delivered it.
That was very, very reassuring in the very, very difficult and dark times during the pandemic.