A livery cab driver plowed into a woman and her 4-year-old son as she was walking him to nursery school in the Bronx today, nearly killing the boy, cops said.

The 27-year-old man was driving a black Lincoln southbound on Broadway at 230th Street around 8:30 a.m., when he rammed into the 41-year-old Bronx woman and her son crossing at the intersection, cops said.

The victims were rushed to St. Barnabas Hospital, where the boy was listed in critical condition.

His mother was listed in stable condition.

The driver stayed at the scene and was not charged.