The constituencies going to the hustings are Kharagpur Sadar in West Midnapore district, Karimpur in Nadia and Kaliaganj in Uttar Dinajpur district.
Trinamool Secretary General Partha Chatterjee announced that Pradip Sarkar would be the party nominee from Kharagpur Sadar, Tapan Deb Singha from Kaliaganj and Bimalendu Singha Roy from Karimpur.
Golam Rabbi, a lawyer, would be the Left Front-backed CPI-M candidate from Karimpur, LF Chairman Biman Bose announced.
The Congress ticket from Kaliaganj has gone to Dhitasree Roy, while Chittaranjan Mandal is the party contestant from Kharagpur Sadar, state party President Somen Mitra announced.
The LF and Congress have entered into an alliance for the bypolls.
Mitra said Congress-Left Front coordination committees would be formed in all the assembly segments to decide on the campaign.
Bose earlier said the LF and the Congress would conduct a joint campaign.
The Kaliaganj seat fell vacant after the incumbent Congress legislator Parmathanath Roy passed away. Kharagpur Sadar is going to the hustings as the sitting MLA - BJP's Dilip Ghosh - was elected to Lok Sabha from Medinipur constituency earlier this year.
Likewise, Karimpur assembly constituency also has a vacancty with its lawmaker Trinamool's Mahua Moitra winning the Lok Sabha battle from Krishnnanagar.
( With inputs from IANS )