"I am ready to have a televised debate over global issues with US presidential nominees at the United Nations," said the president in a press conference this week in Tehran.
Ahmadinejad is due to address the UN General Assembly in New York on September 23, but there has been news of the US State Department stalling his visa process.
He noted that his reasoning for proposing a debate with senators McCain and Obama is to improve relations between the two countries.
"Last year, I said I was ready to meet with (President George W.) Bush. But now he is at the end of his term and (a meeting) will not impact our relations and future," he said.
The US has an agreement with the United Nations, according to which it is obliged to allow foreign leaders to speak before the world body. The agreement requires visas for heads of states visiting the UN headquarters to be granted 'as promptly as possible'.
If President Ahmadinejad attends the annual UN General Assembly meeting, it will be his fourth trip to New York since he took office in August 2005.
During his last trip in September 2007, Ahmadinejad requested to lay a wreath at the World Trade Center, the site of the September 11 attacks, to pay tribute to the victims of the tragedy. His bid, however, was rejected by city authorities.
His proposal to meet and hold a live debate with US President George W. Bush was also rejected. Washington said the White House would only engage in direct talks if Tehran halts its nuclear program.
Ahmadinejad also plans to meet with students, intellectuals, Iranians residing in the US and the media during his upcoming visit.