Marzieh Vahid Dastjerdi, who was endorsed as health minister, was one of 18 nominations by the hardline president, controversially re-elected in June.
Ahmadinejad's two other female nominees for ministerial posts - Fatemeh Ajorlou as welfare and social security minister, and Susan Keshavarz as education minister - were rejected by the legislature.
Parliament backed the president's choice of defense minister, Gen. Ahmad Vahidi, who is wanted in Argentina for the 1994 bombing of a Jewish cultural center that killed 85 people. At the time of the attack, Vahidi was the commander of the Quds Force, a special unit of Iran's Revolutionary Guard.
Most of Ahmadinejad's ministerial choices were approved by the conservative-dominated parliament, providing a boost to the president's authority after months of political disputes following the June election. Opposition parties said the vote was rigged, and the violent crackdown on street protests that followed the election sparked international criticism.