The relatively large number of party members at that time consisted mostly of foreign workers and Germans.
However, at the beginning of the 20th century, the party began to gradually grow and gain more support in other parts of Croatia, especially in Sisak, where Josip Broz Tito, who later become president of SFR Yugoslavia, joined the SDSHiS in 1910.
One part of its membership, led by Vitomir Korać, decided to operate in the People's Committees, in order to thus fit into the new state structure, while the second part, led by Đuro Cvijić and Vladimir Ćopić, rejected reformism, and had become members of the Socialist Labour Party of Yugoslavia (Communists) in 1919.
Yugoslav historiography often stated that the "majority", the left wing of the party, sent the delegation to the national congress in Belgrade, and that Đuro Cvijić, at that time secretary of the Zagreb organization, protested against its "opportunistic" leadership.
The hundredth anniversary of the establishment of the SDSHiS was chosen as the date on which the SDS merged into the Social Democratic Party of Croatia (SDP).