The offer by Ahmadinejad came at news conference Monday as he steps up his campaign for his re-election in the June 12 presidential vote.
If returned to office, Ahmadinejad says he wants to meet Obama during the U.N. General Assembly in September to debate "world issues and the way toward peace."
Ahmadinejad is in a four-way race against a fellow hard-liner and two pro-reform candidates.
The campaign has grown more bitter in recent days with reformists accusing authorities of trying to undercut their strength by blocking the social networking site Facebook.