"The government and nation of Turkey has always clearly supported the nuclear positions of the Islamic republic of Iran, and will continue to firmly follow the same policy in the future," Erdogan was quoted as saying in the statement issued by Ahmadinejad's office.
Ahmadinejad thanked Turkey for its "clear and frank" stance on the issue, the statement added.
The exchange occurred on the last day of a two-day visit Erdogan was making to Iran to discuss the nuclear issue and bilateral ties.
The Turkish prime minister was to hold talks later with Iran's supreme leader, Ayatollah Ali Khamenei, before flying home.
Erdogan flew into Iran on Wednesday from South Korea, where he attended a nuclear security summit alongside other leaders, including US President Barack Obama.
Obama told the summit that "time is short" for a diplomatic solution to the standoff with Iran and urged Iran's leaders to engage in the talks with a "sense of urgency."