Iranian state television said the first Iranian-built destroyer was launched on Friday in a ceremony attended by supreme leader Ayatollah Ali Khamenei.
"The first domestically made destroyer Jamaran was launched this morning and joined Iran's naval forces in the southern waters of the Persian Gulf," state television IRIB reported. It did not give the location of the launch.
The report showed footage of the warship and said it was equipped with torpedoes and electronic radar. The ship is 94 meters long and more than 1,500 ton, it said. Much of Iran's naval equipment dates from before the 1979 Islamic revolution and is US-made.
Tension is high in the long-running international row over Iran's nuclear program, with Western powers calling for a fourth round of UN sanctions against Tehran for refusing to halt uranium enrichment.
The West fears Iran is seeking nuclear weapons. Tehran says it plans only civilian nuclear facilities.
The UN nuclear watchdog said in its latest report it feared Iran might be working now to develop a nuclear payload for a missile.
The United States and its western allies say they want a diplomatic solution but have not ruled out military action against the Islamic republic.
The United States said in January it had expanded missile defense systems in and around the Gulf – a waterway crucial for global oil supplies – to counter what it sees as Iran's growing missile threat.
Iran condemned the move and accused Washington of seeking to stoke "Iranophobia".