With more than 95 percent of precincts counted, just 8.65 percent of the total eligible to vote, or 226,653 people, were in favor of holding the mooted referendum, the electoral court reported.
At least a quarter of eligible voters needed to endorse the initiative in the non-binding public consultation, held after supporters of the referendum gathered more than 52,000 signatures.
The organizers conceded defeat earlier Sunday, shortly after polls closed.
Opposition lawmaker Pablo Abdala, one of the main promoters of the movement to repeal the law, told a local television station the vote "closes a cycle," adding the issue was resolved for now.
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But pro-life campaigner Lorna Marchetti said on Twitter that efforts to repeal the law would continue.
Last October, Uruguay President Jose Mugica signed a bill making his country only the second in mainly Catholic South America to legalize abortion.
The law allows women to have abortions with no questions asked up to 12 weeks into a pregnancy, and under certain conditions after that.
The first South American country to legalize abortion was English-speaking Guyana in 1995. Cuba, a Latin American nation in the Caribbean, did so in 1965 and the procedure is also legal in Mexico City.