Pappu Yadav, a Lok Sabha from Madhepura in Bihar, was on Monday sworn in by Speaker Somnath Chatterjee.
An accused in the murder of Communist Party of India-Marxist leader Ajit Sarkar, Yadav took the oath in Hindi.
Speaking during the Zero Hour, he charged the media with hounding him and his family.
Yadav was elected in a bypoll in October last year on a Rashtriya Janata Dal ticket after Railway Minister Lalu Prasad vacated the seat.
He was shifted from Beur Jail in Patna to Tihar Jail in Delhi following an apex court order.
More from rediff