The meeting took just a few days ahead of the commencement of the Parliament's Winter Session.
RJD leaders Lalu Prasad and his wife Rabri Devi, both former chief ministers of Bihar, were present at the meeting apart from JD(U) chief Sharad Yadav and former chief minister Nitish Kumar, JD(S) chief and former prime minister HD Deve Gowda and INLD's Dushyant Chautala.
The Left was, however, conspicuous by its absence at the meeting although it had initiated the formation of the Third Front before this year's Lok Sabha election.
Nitish Kumar said after the meeting that the plan is to face the BJP unitedly in the parliament and accused the Narendra Modi government of not doing enough to bring back the black money stashed abroad. He also said the regional parties have decided to work together at the moment and will see whether they will merge in future.
Modi's BJP, with 282 seats, has a single majority in the 545-member Lok Sabha. Mulayam Singh Yadav's Samajwadi Party has five seats, RJD four seats while the JD(U) and JD(S) and INLD have two seats each in the Lower House of the parliament.
In Bihar, arch-rivals Lalu Prasad and Nitish Kumar recently buried their differences to contest the bypolls together in August to stop the BJP. The grand alliance, also comprising the Congress and NCP, succeeded to check the BJP. The INLD and NCP though failed to counter the BJP in the assembly elections in Haryana and Maharashtra, consecutively, where ir finished as the single largest party.