Sabir Ali who was re-elected to Rajya Sabha on a JD-U ticket, on Monday took oath in the House.
Ali, who was elected to the Rajya Sabha in 2008 as an LJP nominee, took oath in Urdu swearing in the name of Almighty.
Last week, he was elected unopposed in a by-poll for one seat in Bihar.
After taking oath, Ali went up to the Chairman Hamid Ansari to greet him. Ansari congratulated him.
Pankaj Bora, who was elected to the Upper House from Assam as a Congress candidate, was, however, not present to take oath.
Bora, Assam chief minister Tarun Gogoi's press adviser and former minister, was elected unopposed to the Rajya Sabha to fill the vacancy caused by the death of sitting Congress member Silvius Condpan in October.