"Either I am not fit for the Congress, or the Congress is not fit for me. I am quitting the Congress," he had told the media in Hisar.
Sampat Singh said he had helped the Congress form the government in Haryana in 2009, but he was not given his due.
He said he was peeved at former Chief Minister Bhupinder Singh Hooda for not intervening in ticket allocation in Hisar district.
According to him, at least 40 strong party candidates were ignored at the time of ticket allocation.
In 2009, Sampat Singh had resigned from the Indian National Lok Dal (INLD) and joined the Congress.
The 90-member Haryana Assembly will go to the polls on October 21, while the results will be declared on October 24.