Party's decision came days after Fernandes filed his nomination papers as an independent from Muzaffarpur parliamentary constituency.
Nitish Kumar said the decision of Fernandes' expulsion was taken after the former Union Minister decided to contest the elections as an independent.
"After Fernandes decided to contest election as an Independent, he is no more in the JDU. The JDU has no relation with Fernandes or any one who is contesting elections against the party's decision," Kumar said at a press meet here.
Fernandes, who had been denied a party ticket for the 2009 poll on grounds of his failing health, had Wednesday, Apr 1 filed his nomination papers.