"Gholam-Ali Khoshroo has been chosen as the Islamic republic's permanent ambassador to the United Nations in New York," the foreign ministry said, quoted by IRNA.
Khoshroo, ambassador to Switzerland since July 2014, previously served under current President Hassan Rouhani as a member of an Iranian team negotiating with the EU on its nuclear programme.
A former deputy foreign minister, the 60-year-old diplomat already served at the United Nations between 1989 and 1995.
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The foreign ministry renewed its "protest" over the US refusal to grant a visa to Hamid Aboutalebi because of alleged links to the hostage crisis that led to a break in diplomatic ties between the two countries that is still in effect.
Aboutalebi, a former ambassador to the EU, has insisted he was not part of the hostage-taking in November 1979, when Islamist students who had overthrown the pro-Western shah seized the US embassy, but he later joined the student group.
He has said he worked as a interpreter when the students released 13 women and African Americans.
The remaining 52 diplomats spent a total of 444 days in captivity.