The parties had already said they would not field candidates in Amethi and Rae Bareli, represented by Congress president Rahul Gandhi and UPA chairperson Sonia Gandhi.
Uttar Pradesh has the largest share of 80 in the 543-member Lok Sabha.
The two parties named the seats distributed among them in a statement signed by SP president Akhilesh Yadav and BSP chief Mayawati. The 37 seats in the SP quota include Kairana, Moradabad, Sambhal, Rampur, Mainpuri, Firozabad, Badaun, Bareilly, Lucknow, Etawah, Kanpur, Kannauj, Jhansi, Banda, Allahabad, Kaushambi, Phulpur, Faizabad, Gonda, Gorakhpur, Azamgarh, Varanasi and Mirzapur.
The BSP will contest from Saharanpur, Bijnor, Nagina, Aligarh, Agra, Fatehpur Sikri, Dhaurahara, Sitapur, Sultanpur, Pratapgarh, Kaiserganj, Basti, Salempur, Jaunpur, Bhadohi and Deoria, among other constituencies.
Apart from Amethi and RaeBareli, the alliace has left Muzaffarnagar, Mathura and Baghpat seats for Ajit Singh's RLD
The SP-BSP, once arch-rivals, came close during the parliamentary by-polls in Gorakhpur and Phulpur recently wherein the BSP supported SP candidates who succeeded in winning both the seats - Gorakhpur vacated by Chief Minister Yogi Adityanath and Phulpur by his deputy Keshav Prasad Maurya.
In the 2014 Lok Sabha polls, the SP had won five seats, while the BSP failed to win any seat. In the 2017 assembly polls, SP and BSP got 22 per cent votes each. In 2019, if both the parties continue to have a say in their traditional vote bank, the combine can create hurdles for the Bharatiya Janata Party (BJP).
In the politically-crucial Uttar Pradesh, there are about 22 per cent Dalits, 45 per cent OBCs and 19 per cent Muslims, whose vote share will be decisive in the general elections this year.