A woman walking her dog found a newborn baby in a plastic Walmart carrier bag that had been left on the street.
The tiny girl was alive and still had about three inches of umbilical cord attached to her stomach.
She was rushed to hospital in Houston, Texas, where - miraculously - she is described as being in a 'good condition'.
Police are now searching for the mother who dumped the child in the bag shortly after delivering her.
Sgt Gordon Trott, of the Harris County Sheriff's Office, said an unnamed woman walking her pet at around 7pm came across a Walmart bag left near a fence in the Cypress section of Houston.
The woman's dog had picked up a scent and led her to the bag. At first, the pet owner thought that someone had dumped a dead animal, but when she opened the parcel, she found the little girl inside.
According to officials, the child was naked, but her body temperature was normal, suggesting that she had not been outside for a long time. Her umbilical cord had not been clamped, but someone made sure to clean her up after birth.
Officials with the Harris County Sheriff's Office Crimes Against Children Unit are now working to find the mother, but they have few leads since there are no surveillance cameras in the area where the newborn was abandoned.
"If it had not of been for the resident that came out to walk her dogs, that child may have laid there all night, and possibly would've died," said Sgt Trott.