Iranian state media reported on Monday that the nation's Russian-built nuclear power plant will start generating electricity in the next two months.
The Fars news agency said the Bushehr complex is in its final phases of testing. It is planned to be the first in a network of nuclear power stations in Iran.
Russia, which supplied the reactor, is training Iranians to operate the facility.
Iran is facing international sanctions over its disputed nuclear program.
Iran says the program is to be used for peaceful means, while Western nations fear Tehran is building the capability for a nuclear weapon.
The Bushehr project has been set back by technical problems and delays.
The International Atomic Energy Agency, of which Iran is a member, says it is monitoring the Bushehr developments.