Meira Kumar is pitted against the BJP's Chedi Paswan, a former minister, and the ruling Janata Dal-United's K.P. Ramiah, a former IAS officer.
Nitish Kumar will launch his campaign March 25 addressing four public meetings a day, JD-U state president Vasisht Narain Singh said.
JD-U president Sharad Yadav, who is contesting from Madhepura, will be another major attraction.
RJD chief Lalu Prasad has been at it for some time.
"Lalu has been addressing three to four public meetings daily and trying to reach out to as many people as possible in rural areas," RJD leader Ejaj Ahmad said.
