Ali Akbar Soltanieh will replace current Iranian ambassador to the IAEA Mohammad-Mehdi Akhoundzadeh.
Soltanieh, who previously held the same post in the 1980s under the Presidency of Mir-Hossein Moussavi, has in the past been the chief of the Atomic Energy Organisation of Iran (AEOI).
In recent years, he headed the politico-international bureau in the Iranian Foreign Ministry.
He had been active in negotiations with officials of the European Union over Tehrans suspected nuclear weapons program.
Akhoundzadehs replacement comes after hard-line Iranian President Mahmoud Ahmadinejads Foreign Ministry summoned some 40 of Irans ambassadors and charge daffaires to Tehran, in a massive purge of the countrys foreign service.
The envoys made up nearly half the fleet, including those involved in the countrys nuclear negotiations with the European troika Britain, France, and Germany.