Fianna Fáil MEP Brian Crowley has confirmed he will not seek re-election to the European Parliament in May.
The Ireland South MEP made the announcement at a press conference in Cork today.
The 54-year-old has served in his current role since 1994, making him the longest serving Irish representative in the European Parliament.
However, a "sustained bout" of ill-health over recent years has forced his decision to retire from public life.
Mr Crowley said: “It breaks my heart to leave a job I absolutely love.
“However, I count my blessings. No one received more support, in sickness and in health, than me from my constituents over the past 25 years. It has been a privilege and a joy to serve such wonderful people."
Fianna Fáil leader Micheál Martin paid tribute to the retiring politician.
Deputy Martin observed: “Brian was dedicated and dogged in serving the people that voted for him in great numbers. He approached all issues with great enthusiasm and detail.
“In recent years, Brian’s health has suffered and I understand that his decision to retire will not have been an easy one, but I also know that Brian is a person of great resilience and great faith and I wish him the very best as he works to achieve a full recovery to good health."