Ahmadinejad said the talks will focus on "reaching new decisions on the possible threats" from Israel, adding that Iran and Syria "stand at the forefront of the resistance to the Zionist regime."
Speaking at the airport in Tehran before leaving for Syria, the Iranian leader said, "The Zionist regime and its supporters in the region are quickly approaching a dead end. The situation whereby the Zionists continually threaten countries near occupied Palestine makes it necessary for Iran and Syria to reach new decisions to deal with the possible threats from the Zionist regime."
Ahmadinejad's visit comes as the US announced the nomination of a career diplomat to become the first US ambassador to Damascus since 2005 and lifted an advisory on security concerns in Syria.
Washington's overtures to Syria, Iran's closest ally in the Arab world, coincide with rising US tension with Tehran.
About two weeks ago Ahmadinejad said during a telephone conversation with Assad that Israel should be resisted and finished off if it launched military action in the region.
"We have reliable information ... that the Zionist regime is after finding a way to compensate for its ridiculous defeats from the people of Gaza and Lebanon's Hezbollah," he told the Syrian leader.
"If the Zionist regime should repeat its mistakes and initiate a military operation, then it must be resisted with full force to put an end to it once and for all," Ahmadinejad said.
Reuters and AP contributed to the report