Chakradhar Paik, the Deputy CLP leader, resigned to protest against denial of ticket to him.
"I have resigned from the primary membership of the Congress," Paik told reporters here.
He added that he has sent his resignation letter to party president Sonia Gandhi.
On his future course of action, the MLA from Mohana said he would take a decision after discussing with his supporters.
In his resignation letter, Paik said though he held important posts in the party and belonged to the tribal community, he was denied a party ticket for the forthcoming elections.
Along with him, a number of Gajapati district leaders resigned from the party, Paik said.
CLP leader Bhupinder Singh, also the leader of the opposition in the Assembly, resigned and joined the ruling BJD on March 8.