Ulster and Ireland forward Ferris retires
Ireland's flanker Stephen Ferris (right) runs towards Italy's Sergio Parisse during their 2011 Rugby World Cup match at the Otago Stadium in Dunedin on October 2, 2011 - by Christophe Simon
"It is every young rugby player's dream to represent their province and their country and I have been enormously privileged to have done both," said Ferris, 28, who won 35 caps for Ireland.
Ferris turned out for Ireland at the 2011 Rugby World Cup in New Zealand and played in all five matches of their 2009 Grand Slam success in the Six Nations.
He toured South Africa with the British and Irish Lions later in 2009 and scored two tries, but injuries prevented him from making any Test appearances.
His last international appearance for Ireland came against England in the 2012 Six Nations.
"I have shared a pitch with so many talented players over the past nine years and I want to thank my team-mates at Ulster and Ireland for the support that they have given me," Ferris added in a statement released by Ulster.
Ferris also thanked the Irish Rugby Football Union, the back-room staff at Ulster, and his family, adding: "I have had a great career, met many wonderful people, and I hang up the boots with no regrets."
Ferris made his Ulster debut aged just 20 in 2005 and went on to make 106 appearances for the province.
Having spent 16 months on the sidelines with an ankle injury sustained in November 2012, he made his return in March and played his final game against Saracens in the European Cup quarter-finals.
Ulster director of rugby David Humphreys said: "I would like to thank Stephen for the outstanding contribution that he has made to Ulster Rugby.
"While we are sorry to be losing Stephen, we recognise and celebrate the exceptional rugby career that he has had and wish him every success in the future."