An enraged and naked mother repeatedly slammed her 6-month-old baby boy to the ground outside a Mount Vernon church Friday, police say.

Witnesses say the 23-year-old woman appeared disoriented before she picked up her child over her head and smashed him against the concrete in front of 214 East Lincoln Ave. as shocked bystanders looked on.

The child was taken to Mt. Vernon Hospital, where he is listed in critical condition. He is expected to be transferred to Westchester Medical Center for further care. His mother was also taken to the hospital where she will undergo a psychiatric evaluation.