He led the Congress to a two-thirds majority in the Arunachal Pradesh Assembly elections.
Governor Gen (retd) JJ Singh administered the oath of office and secrecy to 54-year-old Khandu, who returns as Chief Minister for a consecutive second term, at the Durbar hall of the Raj Bhavan.
He was elected unopposed to the Legislative Assembly of Arunachal Pradesh in Mar 1990 from Mukto constituency.
Khandu was re-elected in Mar 1995 from the same constituency and was given the portfolio of Minister of State for Cooperation.
In 2007, he replaced powerful Apang as the Chief Minister who had ruled the tribal state for 23 years
All the newly-elected MLAs were present at the oath-taking ceremony.