The constituencies going to polls in the first phase on April 7 are Tezpur, Kaliabor, Jorhat, Dibrugarh and Lakhimpur.
The fate of Union ministers Paban Singh Ghatowar (Dibrugarh) and Ranee Narah (Lakhimpur), who were renominated by the Congress, would be decided in the first phase.
Other prominent candidates in the fray are BJP state unit president Sarbananda Sonowal (Lakhimpur), Chief Minister Tarun Gogoi's son Gaurav Gogoi (Kaliabor) and former Union Minister Bijoy Krishna Handique (Jorhat).
The last date for filing nomination is March 21. While scrutiny was scheduled for March 22 and the last date of withdrawal of candidature was March 24, the sources said.
Lok Sabha polls in Assam will be conducted in three phases — April 7 (5 seats), April 12 (3) and April 24 (6).