The ANC's National Executive Committee (NEC) made the decision at a meeting on Sunday.
Kgalema Motlanthe, the ANC secretary-general, said in a statement on Monday: "The NEC agreed that, as a consequence of the conclusion of the trial, comrade Zuma should resume his duties as ANC deputy president and his participation in the leading structures of the movement without delay."
Thabo Mbeki, the president, sacked Zuma, 64, as his deputy last June amid a corruption scandal involving Zuma's former financial adviser.
But Zuma kept his post of deputy president of the ANC, although he voluntarily withdrew from acting in that role until the rape case was over.
A Johannesburg High Court judge acquitted Zuma last Monday of charges of raping an HIV positive 31-year-old family friend at his Johannesburg home last November.
Supporters of Zuma insist he
Zuma, who apologised for having consensual sex with an HIV-positive woman, declared immediately that he was resuming his normal functions in the ANC, but the party said its NEC would make that decision at Sunday's meeting.
Many of Zuma's rank-and-file ANC supporters have denounced the rape charges as a smear campaign to prevent him from succeeding Mbeki.
Zuma said last week he was willing to seek election as South Africa's next president.
But Zuma still faces a final hurdle when he is expected back in the dock on July 31 on graft charges relating to a multi-billion dollar arms procurement deal.