Both are great-grandsons of former Deputy Prime Minister Devi Lal. Both have been expelled from the primary membership of the party with immediate effect, a party statement said here.
Dushyant Chautala has also been removed from the post of leader of the INLD Parliamentary Board.
The action follows recent activities of both youth leaders and their supporters who were trying to project Dushyant as a Chief Ministerial face in Assembly elections in Haryana to be held around October next year.
"Both Dushyant Chautala and Digvijay Singh had been accused of indiscipline, hooliganism and spreading disaffection within the party against the party leadership during the birthday celebrations of Chaudhary Devi Lal in Gohana on October 7," the INLD statement said.
"He (Om Prakash Chautala) conveyed to the party office that he did not need any outside evidence since he was a witness to the indiscipline and unruly scenes that also continuously interrupted his speech on that day but still he had referred the matter to the Disciplinary Action Committee of the party.
"The committee has concluded that both are guilty as charged," the party statement said.
The move is likely to affect the INLD prospects in the forthcoming general elections and Assembly polls.
"In view of the fact that Dushyant Chautala and Digvijay Singh were members of his immediate family, it was not an easy decision for him to make. But he added that all his life he had followed the principles and ideals of Jana Nayak Chaudhary Devi Lal, for whom the party was always bigger than the individual or any family member.
"Thus he had to make a choice between the party and members of his family and he had chosen the party and decided to concur with the conclusions of the Disciplinary Committee. Accordingly, he had instructed the party office that his decision is immediately put into effect," the statement said.
(With inputs from agencies.)