Ahmadinejad is expected to meet with both Raul and Fidel Castro during his less than 24 hours on the island. He also plans to speak at the University of Havana.
Cuban state television broadcast images of Vice President Esteban Lazo greeting the Iranian leader at the airport Wednesday.
Ahmadinejad previously visited Venezuela and Nicaragua on his trip. He has been promoting friendships with allies in the Americas, shortly after Washington imposed tougher sanctions on Tehran over its nuclear program.
He travels to Ecuador next.