The by-elections to Gaibandha-3, Bagerhat-4 and Dhaka-10 constituencies will be held on March 21.
The Election Commission announced the schedule at the Nirbachan Bhaban on Thursday.
February 19 is the deadline for submission of nomination paper. They will be scrutinised on February 23 and the last date for the withdrawal of candidacy is February 29.
Gaibandha-3 constituency fell vacant following the death of Awami League MP Dr M Yunus Ali Sarker on December 27 last, UNB reported.
Bagerhat-4 constituency fell vacant following the death of Awami League MP Dr Mozammel Hossain on January 10.
Besides, Dhaka-10 AL MP Sheikh Fazle Noor Taposh resigned on December 29 to contest in the Dhaka South City Corporation election.