The IFP snatched a ward from the ANC in a by-election in Nkandla in KwaZulu-Natal, where President Jacob Zuma's private home is based, according to results released by the Independent Electoral Commission.
The Inkatha Freedom Party's Thembinkosi Francis Nxumalo won 54.99% support.
The ward was previously held by the African National Congress, whose candidate, Bongumenzi Mninimuzi Ngcobo, won just under 50% of the vote in the last municipal by-elections.
Nkandla has been in the news recently because this is where Zuma's private residence has recently been upgraded, at a reported cost of more than R200 million.
The matter is currently being investigated by a public works task team.
The Nkandla ward became vacant after the councillor died of natural causes.