Ahmadinejad's two-day visit -- his first official visit to Azerbaijan -- is expected to focus on bilateral relations, energy cooperation, and issues related to the Caspian Sea, RFE/RL's Azerbaijani Service reported.
The two leaders are also expected to discuss Azerbaijan's Qabala radar base, which Russia has offered to the United States as part of its proposed missile-defense shield. Washington says the program is meant to defend Western targets against missile attacks from Iran.
Ahead of the meeting, Iran's ambassador to Azerbaijan, Nasir Hamidi Zare, said that the issue is important because Tehran "sees peace and stability in Azerbaijan as peace and stability in Iran."
Zare said the talks may also touch on Azerbaijan's sensitive role as an ally of both Iran and the United States.
Ahmadinejad and Aliyev are expected to hold a joint press conference later today.
Activists are planning to hold a rally on August 22 outside the Iranian Embassy in Baku.
Agri Qaradagli, a member of the National Awakening Movement of Southern Azerbaijan, says members of the group will protest what they call Tehran's repression of the national and cultural rights of millions of ethnic Azeris living in northern Iran.
Qaradagli said demonstrators will also call for the release of Azeri political prisoners in Iran.