"News that the respected Ahmadinejad has been killed are false. He is healthy and safe," spokesman Ali Reza Mataji said.
The denial followed Israeli and US attacks on Iran that have killed several senior political and military leaders. Ahmadinejad's home was reportedly hit on Saturday.
Ahmadinejad, who served as Iranian president from 2005 to 2013, has maintained a public profile since leaving office.