The country's media are calling him "the miracle baby".
He was born prematurely to a 14-year-old girl in a shanty town outside the capital, Buenos Aires.
She is said to have panicked and abandoned the boy in a field, surrounded by wooden boxes and rubbish.
Then along came La China, the dog which somehow picked up the baby and carried him 50m to place him alongside her own puppies.
The dog's owner heard the child crying and found him covered with a rag.
The baby, weighing 4kg (8lb 13oz), had some slight injuries, but no bite marks. The owner called the police and the child is now being looked after by the authorities, while a decision is taken about his future.
The frightened mother appeared shortly after her baby was found.
The Argentine media has descended on the shanty town, talking of "the Argentine Romulus and Remus", the founders of Rome, abandoned as babies and rescued by a wolf, nearly 3,000 years ago.
La China, worried about her own puppies, is reported to be petrified by her new found fame, and her owner says he is worried that she is not eating.