Prime Minister Manmohan Singh on Friday took oath as Rajya Sabha member from Assam.
The oath was administered by Chairman Bhairon Singh Shekhawat in his Parliament House chamber.
Dr Singh, who was recently elected unopposed to the Upper House for the fourth consecutive term, took the oath in English.
UPA chairperson Sonia Gandhi and Union Ministers, including Shivraj Patil, Lalu Prasad, Ramvilas Paswan, T R Baalu, S K Shinde, Santosh Mohan Deb, P R Dasmunsi and H R Bhardwaj, were present on the occasion.
A number of Rajya Sabha members, including S S Ahluwalia and Sitaram Yechury, also attended the ceremony.
The prime minister was elected unopposed on May 18 after independent candidate Matang Singh withdrew from the contest.
Asom Gana Parishad candidate Kumar Dipak Das, who too was elected unopposed to the Rajya Sabha from the other seat in the state, was also administered oath by Shekhawat separately. Das took the oath in Assamese.