While Pappu Yadav bagged 3,68,937 votes, Sharad Yadav secured 3,1,728 votes, Election Commission statement said.
BJP's Vijay Singh got an impressive 2,52,534 votes to stand third in the constituency.
Sharad Yadav had to pay the price of his party parting company with BJP, the results indicate.
With today's defeat Sharad Yadav's dream to enter Lok Sabha for the eighth time with a fifth stint from Madhepura seat ended.
Pappu Yadav, who was chosen by RJD President Lalu Prasad, to humble the socialist veteran was acquitted in CPM leader Ajit Sarkar murder case recently by the Supreme Court.
Sharad Yadav had won from Madhepura in 1991, 1996, 1999 and 2009. He was defeated by RJD President Lalu Prasad on the seat in 2004. Madhepura is the the native place of B P Mandal, the architect of Mandal Commission report ensuring reservation to OBCs in government jobs.