"For me, this is the last speech as chairman of the SPD," Schulz was quoted by German media Focus Online as saying. "It's a difficult job at times, but I retire without bitterness and resentment."
The SPD presidium has nominated the SPD parliamentary group leader and former Labor Minister Andrea Nahles as the new Party leader, a decision pending approval.
If Nahles is elected, she will become the first SPD chairwoman in the party's 150-year-history. The election will take place on April 22 at a Party conference in Wiesbaden, Schulz said at the SPD headquarters in Berlin.
The German Press Agency (DPA) reported that Hamburg's First Mayor Olaf Scholz, who will probably become Germany's finance minister in the upcoming new government, will provisionally take over the position of SPD leader until the April election. Several state associations had formally objected to the immediate takeover of the top office by Nahles.
The change is a hope by the party's leadership committee to contain the bitter infighting which has continued despite Schulz's resignation from the role as SPD leader, as well as his more recent surrender of the prospective post as foreign minister in a new "grand coalition", referring the coalition between SPD and German Chancellor Angela Merkel's Conservatives Union.
Schulz's announcement came after a turbulent week for him. Last Wednesday, the SPD reached an agreement with Merkel's Union in formal government coalition negotiations, a move likely to end the longest ever new government vacuum after the Sept. 24 federal elections.
However, Schulz announced two days later that he gave up the bid for foreign minister in the new government after he was heavily criticized by his party comrades for it as he previously said he wouldn't serve in the next German government.
Before the elections, Schulz said the SPD would not form another grand coalition with the Union. But he changed minds after the Union failed to form the government with two small parties.
Schulz, who is also former European Parliament president, was elected as SPD chairman with unanimous votes in March, but SPD suffered the worst election result since 1949.
The SPD is currently divided over whether to form a renewed "grand coalition". Despite the deal reached between the two parties, it is subject to the vote of SPD's 464,000 party members in early March.