A 33-year-old woman from Kamesh in Uitenhage is expected to appear in court soon following her arrest for murder.
Spokesperson Sergeant Majola Nkohli says police attended to a complaint on Tuesday afternoon about a woman attempting to commit suicide.
Officers rushed to the house in Acacia street where the woman had locked herself with her 6-month-old baby boy in her bedroom.
Nkohli says police forced open the door and found the baby, with visible injuries, dead on the bed.
The mother had open wounds to both her wrists.
The woman was arrested and first taken to a hospital where she is currently under mental observation.