The ANC has won three of the five municipal ward by-elections held on Wednesday, the Independent Electoral Commission (IEC) said.
The remaining two seats went to the Democratic Alliance and Inkatha Freedom Party, the IEC said in a statement on Thursday.
The elections were held in the Eastern Cape, Free State, KwaZulu-Natal, and Limpopo.
Voter turnout varied between 60.29 percent and 33.26 percent, with an average of 45.75 percent.
In the two by-elections held in the Eastern Cape, the new councillors were both from the African National Congress. They were Zephaniah Zamekile Papiso in the Emalahleni (Lady Frere) municipality. Tsiliso Patrick Motjope won in the Matatiele municipality. In both the party retained the ward.
In Limpopo, Mashilo Moses Kgwatalala of the ANC won in the Blouberg (Bochum/My Darling) municipality. The party retained the ward.
In the Free State, the Democratic Alliance's Roquet Beneke won in the Matjhabeng (Welkom) municipality. The ward was retained by the party.
In KwaZulu-Natal, Zanele Sithole of the Inkatha Freedom Party won in the Nqutu Municipality, with the party retaining the ward.