One of the 80 Lok Sabha seats in Uttar Pradesh, Kushi Nagar parliamentary constituency came into existence in 2008 following delimitation exercise. Three of the five assembly segments in Kushi Nagar were in Padrauna Lok Sabha constituency which ceased to exist following the 2008 delimitation.

In the first election held in Kushi Nagar Lok Sabha seat, Congress' RPN Singh (Ratanjit Pratap Narain Singh) emerged victorious and went on to become a Union Minister in Manmohan Singh government. Singh, popularly known as Raja Saheb, comes from erstwhile family of Padrauna. His father Kunwar Chandra Pratap Narain Singh (CPN Singh) was two-term MP from Padrauna Lok Sabha constituency.

Ram Nagina Mishra of the Bharatiya Janata Party (BJP) won from Padrauna four consecutive elections and represented the seat in Lok Sabha from 1991 to 2004.  Baleshwar Yadav of National Loktantrik Party won from Padrauna in 2004.

In the 2009 election, after the formation of Kushi Nagar Lok Sabha constituency, RPN Singh defeated Swami Prasad Maurya of the BSP by 21,000 votes. He was, however, defeated by Rajesh Pandey alias Guddu in 2014 by nearly 86,000 votes. 

The BJP has denied ticket to Rajesh Pandey and has instead fielded Vijay Dubey. He is pitted against Congress' RPN Singh and Nathuni Prasad Kushwaha of the Samajwadi Party. 

Kushi Nagar comprises five assembly segments: Khadda, Padrauna, Kushinagar, Hata and Ramkola (SC).

UP is facing a triangular battle between the BJP, the Congress and BSP-SP-RLD alliance. Under the alliance's seat-sharing formula, the Mayawati-led Bahujan Samaj Party (BSP) is contesting on 38 Lok Sabha seats of the total 80 seats, Akhilesh Yadav's Samajwadi Party on 37 seats and the Chaudhary Ajit Singh's Rashtriya Lok Dal (RLD) on three seats. The alliance has left two for Congress' Sonia Gandhi (Rae Bareli) and Rahul Gandhi (Amethi). 

In the seventh phase of Lok Sabha polling, 13 seats in Uttar Pradesh - Maharajganj, Gorakhpur, Kushi Nagar, Deoria, Bansgaon, Ghosi, Salempur, Ballia, Ghazipur, Chandauli, Varanasi, Mirzapur and Robertsganj - are going for polls.

In 2014 election, all of these 13 seats were won by the BJP with Prime Minister Narendra Modi securing his victory from Varanasi.