Governor Vakkom B. Purushothaman administered oath of office and secrecy to Thanhawla and his 11 ministerial colleagues at a glittering ceremony at Raj Bhavan. Seven of the ministers are of cabinet rank, while the rest are ministers of state.
Immediately after assuming office, Thanhawla said that his government's priorities would be increasing power generation in the state, expediting hydropower projects and improving road connectivity, besides developing other basic infrastructure.
"The solution of the unemployment problem and other social issues would be the other matter of priority for my government," he told reporters.
This is the sixth time that the Congress has come to power in the mountainous state. The party has had consecutive terms twice in Mizoram, a state which shares borders with Myanmar and Bangladesh.
In the Nov 25 Mizoram assembly elections, results of which were declared Dec 9, the Congress bagged 34 of 40 seats, leaving the opposition Mizo National Front (MNF) with only five seats. One seat went to the Mizoram People's Conference (MPC).
Thanhawla, 71, who assumed the chief minister's office for a fifth term Saturday, won from two assembly seats -- Serchhip and Hrangturzo (both in central Mizoram) -- defeating his MNF and MPC rivals respectively.
Also the state Congress chief, former journalist Thanhawla who established the party's base in the Christian-dominated and tribal majority northeastern state in the 1970s, has been elected to the assembly for a record ninth time since 1978. He first became chief minister in 1984.
The first session of the newly constituted seventh Mizoram assembly will begin from Monday.
An official notification issued here said that the newly-elected legislators, who won the Nov 25 assembly election, would be sworn-in by the pro tem speaker.
The governor would give his customary address to the house Tuesday.