Analia Bouter was told that her baby, born six months premature, was stillborn.
When she and her husband visited the morgue 12 hours later and opened the coffin, they found the baby girl breathing.
The Argentinean parents have named their baby Luz Milagros, which means miracles, reported the BBC.
Bouter gave birth to Luz in the city of Resistencia a week ago, but the news was only made public to local health officials recently.
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The Chaco province's undersecretary for health, Rafael Sabatinelli, said the case was "disgraceful" and called for a full investigation.
Bouter said, "That night I went with my husband to where the coffin was and he opened it up." She continued, "Immediately I heard her cry."
Infant mortality rates in Argentina have dropped in the past decade, from 18.31 deaths per 1,000 live births in 2000 to 10.81 deaths per 1,000 in 2011, according to the CIA World Factbook.