Polling will also be held in the Jehanabad and Bhabua Assembly constituencies of Bihar the same day. The poll panel said the vote count will take place on March 14.
The elections in the Uttar Pradesh Lok Sabha seats were necessitated after Gorakhpur MP Yogi Adityanath became the Chief Minister while Phulpur MP Keshav Prasad Maurya was appointed his deputy.
Adityanath has represented Gorakhpur five times in the Lok Sabha from 1998. BJP insiders say Bhojpuri actor Ravi Kishan is keen on contesting from Gorakhpur.
The Araria seat fell vacant after the death of Rashtriya Janata Dal MP Mohammad Taslimuddin in September 2017.
The Jehanabad and Bhabhua constituencies fell vacant due to the death of BJP MLA Anand Bhushan Pandey (Bhabhua) and RJD MLA Mundrika Singh Yadav.
The BJP MLA passed away in November. Yadav, a former state Health Minister, succumbed to dengue a month earlier.
The Election Commission said the last date for filing nominations for all five seats is February 20 and the last date for withdrawal of candidature is February 23.
The model code of conduct will come into effect in the concerned districts with immediate effect.