A baby boy, believed to be three-weeks-old, was found on Thursday morning on the N12 near the Joe Slovo Road in Klerksdorp.
A spokesperson for ER24 Russel Meiring says the baby was wrapped in a blanket and showed signs of mild hypothermia.
He says the infant was immediately transported to the Provincial hospital in Klerksdorp for further care.
The incident will now be investigated by the South African police.