Ireland snap up England discard
Farrell will take up the role with the national team after the 2016 Six Nations championship.
Farrell joins the Ireland coaching set-up having been assistant coach with England from 2011 to 2015, as well as defence coach for the 2013 series-winning British and Irish Lions tour.
Previous to joining the England set-up, Farrell coached Premiership side Saracens.
A dual code player, Rugby League and Rugby Union, Farrell played for Wigan (370 caps), England (in League, 11 caps) and Great Britain (League, 34 caps) – before switching to Union and joining Saracens.
He won eight caps for England in Union, including three appearances at the 2007 World Cup.
"It's great to have Andy coming into our coaching team," Ireland coach Joe Schmidt said.
"The quality of his delivery and breadth of his experience as well as the positive impact he had when coaching a number of our senior players during the 2013 Lions tour will add real value for us."
Andy Farrell commented: "To have this opportunity to work with a very talented management and playing group really excites me.
"With a wealth of top class experienced senior players and a fantastic crop of youngsters pushing hard the future is very positive for Irish rugby and I can't wait to get started."
Farrell's contract with the IRFU commences ahead of the June tour of South Africa and runs until the completion of the 2019 World Cup in Japan.
