Sayed Abdel Aal is the new head of the leftist-Tagammu Party after winning internal elections by a single vote Wednesday.
The announcement was made at the party's headquarters in Cairo.
According to the party, Abdel Aal got 239 votes, while his rival Hussein Abdel Razek came second with 238.
The elections were supposed to be held last August, but the party was unable to reach quorum.