Throughout his 108 caps, O'Connell has been arguably Ireland greatest ever lock and has helped his country to three Six Nations Championships, as well as four Triple Crowns and the memorable Grand Slam in 2009.
This gallery looks at the 35-year-old's career from his earliest days with Munster and Ireland comrade Ronan O'Gara, to last year's memorable Six Nations triumph when he lifted the trophy in tandem with Brian O'Driscoll.
Paul O'Connell tackled by Ronan O'Gara
Ireland Rugby Tour 2003 Training
A tearful O'Connell playing for Munster
A dejected Paul O'Connell after leaving the field through injury on his debut.
Paul O'Connell of Ireland celebrates his try back in 2002.
Brian O'Driscoll and Paul O'Connell
Paul O'Connell dejected after Ireland's defeat to Australia in 2008.
Paul O'Connell supported by Rory Best in 2007.
Paul O'Connell celebrates winning the RBS Six Nations Grand Slam in 2009.
Paul O'Connell lifts the trophy in 2009 with John Hayes, Stephen Ferris and Jerry Flannery.
Ireland's Paul O'Connell and Brian O'Driscoll celebrate after 2014 Six Nations win.
WATCH: Paul Mescal, Saoirse Ronan, sex scenes & sci-fi