They were en route from an air force base to a hillside military college in the southern state of Tamil Nadu when the Russian-made Mi-17V5 helicopter came down near the town of Coonoor.
Local television footage showed rescuers and army personnel carrying bodies up steep slopes from the mangled wreckage. Only one of the 14 people on board survived and was in hospital with injuries.
"With deep regret, it has now been ascertained that Gen Bipin Rawat, (his wife) Mrs Madhulika Rawat and 11 other persons on board have died," the Air Force said in a statement.
Rawat, 63, was appointed as India's first Chief of Defense Staff by Prime Minister Narendra Modi's government in late 2019. The position was set up with the aim of integrating India's three military services - the Army, the Navy and the Air Force.