Former Portugal coach Carlos Queiroz has taken charge of the Iran national team on a three-year deal.
Queiroz's appointment comes two weeks after his six-month ban for disrupting an anti-doping test was overturned.
He succeeds Afshin Qotbi whose contract was not renewed after Iran were knocked out of the Asian Cup in the quarter-finals by South Korea in January.
The former Manchester United assistant manager said: "I am in Iran to help the team make it to the 2014 World Cup."
Queiroz had two spells as Sir Alex Ferguson's assistant at Old Trafford and coached Real Madrid.
He was sacked as Portugal coach in September, a week after the Portuguese Anti-Doping Agency banned him for six months for alleged misbehaviour during an anti-doping testing session before the 2010 World Cup.
However, in March, the Court of Arbitration for Sport overturned the ruling, saying "there was no evidence that his behaviour was intended to disturb the doping control".
Mozambique-born Queiroz led Portugal to the last 16 of the World Cup finals in South Africa where they were beaten 1-0 by eventual tournament winners Spain.