Lalu's sons Tej Pratap Yadav and Tejaswi Yadav also took an oath as ministers of Bihar.
According to reports, Tejaswi is likely to be appointed as Bihar Deputy Chief Minister
The ceremony was attended by RJD supremo Lalu Prasad Yadav, his wife and former Bihar chief minister Rabri Devi and their two sons.
Congress vice-president Rahul Gandhi, former Prime Minister H.D. Devegowda, NCP chief Sharad Pawar, his National Conference counterpart Farooq Abdullah and Congress leaders in Lok Sabha and Rajya Sabha Mallikarjun Kharge and Ghulam Nabi Azad were also present at the event.
Former chief minister of Jammu and Kashmir Farooq Abdullah, former chief minister of Jammu and Kashmir and working president of National Conference Omar Abdullah, Hindustani Awam Morcha (HAM) President Jitan Ram Manjhi, Janata Dal (United) leader Sharad Yadav, Himachal Pradesh Chief Minister Virbhadra Singh were also present at the event.
West Bengal Chief Minister Mamata Banerjee and Delhi Chief Minister Arvind Kejriwal also attended the event.
Delegations of leaders poured in here and assembled at the venue as Nitish took his oath as the Chief Minister of Bihar.
Congratulating Nitish Kumar, National Conference (NC) president and former Jammu and Kashmir Chief Minister Dr. Farooq Abdullah today said the senior Janata Dal (United) leader must now start preparing himself to become the next Prime Minister of India.
"It's a new start for India and Nitish should now start making preparations to come to Delhi and become the Prime Minister and we will extend our full support to him for that," Abdullah told the media here.