66-year-old Banerjee was administered the oath by Governor Jagdeep Dhankhar at the "Throne Room" at the Raj Bhavan here in adherence to Covid protocols.
Banerjee, in her trademark white Sari and shawl, took oath in Bengali. The rest of the cabinet and the Council of Ministers will be sworn in on May 9, the birth anniversary of Rabindranath Tagore, sources said.
The newly sworn in West Bengal Chief Minister, Mamata Banerjee said she will hold a review meeting on the situation arising out of Covid-19 in the State today.
"My first priority is tackling the Covid pandemic. I will go to Nabanna now and hold a meeting about the measures we are taking about this crisis... I will hold a press conference at 3 pm and let you know what measures we are taking," said Banerjee.
In the just concluded elections, Mamata Banerjee-led Trinamool Congress won 213 seats in the 294-seat State Assembly while its strongest rival, BJP, garnered 77 seats.