The mom and her 16-month-old were struck by a southbound vehicle near 2nd Avenue around 8 p.m., Bristol Borough police said.
The striking vehicle was then rear ended by a second car also heading south.
The Bucks County Rescue Squad transported the mom and child to Jefferson Torresdale Hospital, and the child was later transferred to St. Christopher's Hospital for Children.
Both drivers remained at the scene and were cooperating with the investigation.
Assisting at the scene were the Bristol Township Police Department, Tullytown Police Department, The Bristol Borough Fire Department along with the Bristol Township Fire Police assisted at the scene.
Both the mother and child were listed in critical condition.
Due to the extent of the injuries the Bucks County District Attorneys Homicide by Auto Unit was assisting Bristol Borough Police with the investigation
Click here to follow Daily Voice Lower Merion-Narberth and receive free news updates.