Former prime minister Manmohan Singh filed nomination papers for the by-poll to Rajya Sabha from Rajasthan on Tuesday.
Manmohan filed four sets of nomination papers in the chamber of returning officer in Rajasthan Assembly.
He expressed gratitude to the Congress party for nominating him and expressed condolence for BJP's Madan Lal Saini, following whose death the seat got vacant in June.
Manmohan said that he will do whatever is possible to promote the cause of the people of the state.
"I express gratefulness to the people of Rajasthan and the congress party for giving me this privilege for serving the people of Rajasthan in the council of states. I will do my very best to do whatever is possible to promote the cause of the people of Rajasthan, he added.
The Congress has the majority in the state assembly and Manmohan, thus, is likely to win the by-poll.
Rajasthan Assembly has 200 seats but two seats are vacant.
Congress has 100 MLAs and its alliance partner Rastriya Lok Dal has one seat, Bharatiya Janata Party has 72, Bahujan Samaj Party 6, Bharatiya Tribal Party, Communist Party of India (Marxist) and Rashtriya Loktantrik Party have 2 seats each, 13 are independents.