Forty-four candidates will be competing for the top spots on the list in the hopes of making it into the 21st Knesset, while the party continues to drop in the polls.
With voter turnout expected to be low, political deals struck in recent days and lists of recommended candidates will likely play a big role in the primaries.
Different groups, such as the Histadrut Labor Federation and prominent kibbutzim activists, have distributed lists of recommended candidates
Labor's top 10 only has seven available spots. The first spot is reserved for party chairman Avi Gabbay, while Gabbay also has the second and tenth spot reserved for candidates of his choosing.
Gabbay himself has decided not to publicly release his own list of recommended candidates, but privately he has recommended six candidates: Shmuli, Yachimovich, Peretz, Shaffir, Bar-Lev and Michaeli. He is waiting for the results of the primaries to decide whether to use his two reserved spots, with Labor officials estimating Gabbay won't use his reserved spots unless he could recruit a prominent figure to join the party.
Despite the pessimistic polls, some of the new candidates in the Labor race have launched an intensive campaign, though their chances of securing a realistic spot on the list are still very low.
Among the new candidates are some prominent figures and close associates of senior party members, including TV presenter Emilie Moatti, who has close ties to Gabbay, and Yair Fink, who shared his campaign with Yachimovich. Other new candidates include Rabbi Gilad Kariv, who heads the Reform Movement in Israel; journalist Henrique Cymerman; Gil Beilin, who is the son of former minister Yossi Beilin; and Michal Chernovitzky, who formed the ultra-Orthodox faction in Labor.
Within the party there are several interesting political struggles. MKs Yachimovich and Peretz, both former leaders of the party, were once allied but have recently become bitter rivals. Each hopes to rank higher than the other in a battle for status and prestige, which might also indicate whether they can run for the party's chairmanship again in the future.
Meanwhile, MK Eitan Cabel is fighting for his place in the party, claiming he is paying a political price for his campaign to replace Labor chairman Gabbay.
MKs Shmuli and Shaffir, both leaders of the 2011 social protest, are secret rivals, even though they don't give public expression to this rivalry. Shmuli is considered very popular and strong within the party and is aiming for the top spot on the list.
MKs Swid and Michaeli, meanwhile, are also fighting for the spot of the third most powerful woman in the party, after Yachimovich and Shaffir.