The RJD's 80 new legislators on Friday authorised party chief Lalu Prasad to choose the party leader in the house, amid signs that it could be his son Tejaswi Yadav.
The Rashtriya Janata Dal's legislature wing is to formally meet here on Saturday.
The RJD is the biggest party in the tri-party Grand Alliance with Chief Minister Nitish Kumar's Janata Dal-United (JD-U) and the Congress.
RJD sources said Lalu Prasad's younger son Tejaswi Yadav, a former cricketer, is set to be the leader of its legislature party.
Lalu Prasad earlier said that Tejaswi Yadav will play an important role in the new Bihar government.
The younger Yadav was elected from Raghopur, which was once represented by his mother and former chief minister Rabri Devi.
The RJD legislators, however, agreed unanimously that Nitish Kumar will be the leader of the Grand Alliance, which crushed the four-party alliance of the Bharatiya Janata Party (BJP) in the assembly elections.
The Congress will also hold a meeting of its newly elected legislators here on Saturday.
The JD-U's newly elected legislators will formally elect Nitish Kumar as the leader of the legislature party on Saturday.
He will then be picked the leader of the legislature party of the Grand Alliance at a joint meeting of the three parties.
Nitish Kumar has said he will recommend the dissolution of the outgoing 243-member state assembly on Saturday after holding the last meeting of his cabinet.
He will stake claim to form his new government the same day.
According to JD-U leaders, Nitish Kumar will again take oath as chief minister on November 20 along with a 36-member council of ministers.
Nitish Kumar was declared the chief ministerial candidate by the Grand Alliance. Lalu Prasad called him the 'dulha' (bridegroom) of the victorious alliance.
The RJD won 80 assembly seats followed by the JD-U with 71 and the Congress with 27 seats. The BJP bagged 53 seats and its three allies a mere five seats.
According to indications, there will be 16 ministers from the RJD, 15 from the JD-U and five from the Congress in the new government.
