Former JD(S) MLC Ramesh Babu joined the Congress in the presence of KPCC president D.K. Shivakumar and Leader of the Opposition Siddaramaiah on Saturday.
He was welcomed with a party shawl by both senior leaders.
Mr. Babu quit the JD(S) after he was sidelined by the State JD(S) leaders, sources said.
Mr. Shivakumar said many leaders who quit the party have shown interest in rejoining. A committee had been formed for this. The leaders would be readmitted after the committee scrutinized their applications, he added.