His comments came after Mostafa Mohammad Najjar, the defence minister, was the target of an impeachment motion filed by a group of parliament deputies angered over reports that the aged C-130 was ordered to fly despite warnings from its pilot.
Ahmadinejad said on Sunday of last Tuesday's crash: "The government will hold a serious investigation."
Speaking of those killed on board, he said: "But what is important is that they have shown the way to martyrdom which we must follow."
The C-130 workhorse - bought from the United States before the 1979 Islamic revolution and starved of crucial spares by US-imposed sanctions - crashed into the foot of a high-rise housing block after suffering engine failure.
Of the 108 people killed, 68 were journalists travelling to report on military exercises in the south of the country.
"What is important is that they have shown the way to martyrdom which we must follow"
Forty-nine deputies in the Iranian Majlis have backed the impeachment motion. The text of their complaint was not published, but the authorities have been under fire over indications the plane had been forced to fly.
Gholam Ali Hadad-Adel, the parliament speaker, said the motion would be first examined by parliament's legal service, and, if deemed presentable, would be examined by the assembly on 18 December.
According to the official news agency IRNA, the aeroplane did not have a flight recorder although all communications between the plane and the control tower at Mehrabad airport were recorded.
It said a 25-member team made up of armed forces personnel was probing the cause of the disaster.