0858 GMT August 22, 2019
Najafi, 67, was sentenced to death last month after being convicted of shooting dead his second wife, Mitra Ostad, at home on May 28. She was found dead at home with gunshots in her chest.
The pardon was announced by the victim’s brother Masoud Ostad.
Ostad's family had appealed for the Islamic law of qisas [retaliation in kind] verdict.
But her brother said the family had decided to grant him a reprieve, according to a post on his private Instagram account cited by various media outlets.
IRNA said a lawyer for the family, Mahmoud Hajilouei, had confirmed the reprieve.
"My father, my mother and our Mahyar (Mitra's son) forgive Mr. Mohammad-Ali Najafi" after mediation that involved others, he wrote.
"We are happy that we made no deal for the blood of that honorable (person)," he added.
"We hope Mr. Mohammad-Ali Najafi in his remaining years... engages in cleansing himself."
A graduate of the Massachusetts Institute of Technology (MIT), Najafi, was elected mayor of Tehran in August 2017, but resigned in April 2018, citing failing health for leaving the office.
AFP contributed to the above story.