Luz Milagros Veron, 'Milagros' means "miracles" in Spanish, "is stable," with a tube for feeding and respiratory assistance "to help avoid fatigue," said the director of Resistencia's pediatric hospital, Juan Mario Jacobassi.
The five-month-old left the hospital in northeastern Argentina around noon, in the arms of her mother Analia Boutet.
She remains fragile, and her care will continue at home with the help of specialized equipment installed there.
Born on April 3, some three months before her due date, Luz Milagros weighed around 780 grams (1.7 pounds).
Doctors examined her and determined she was stillborn.
But 12 hours later, when the parents went to the morgue to see the body and say goodbye, they were shocked to hear a small whimper and see the baby making small movements.
"She was all covered up and full of something that looked like frost," Bouter told the local press at the time.
The parents had planned to name the baby Lucia Abigail, but changed it to Luz Milagros after the incident.