The child has been admitted to Alder Hey Children’s Hospital in Liverpool where his condition is described as “poorly.”
Police have launched an investigation and have arrested two men and a woman on suspicion of wounding.
Officers were called to an address in Charles Street, Blackpool in the early hours of today.
Paramedics raised the alarm before taking the injured baby to the town’s Victoria Hospital. He was transferred to Alder Hey shortly afterwards.
A police spokesman said they had been “contacted by the ambulance service at about 1am to report that a one-month-old baby boy had been injured at an address on Charles Street.
“Three people, two men aged 18 and 33 and a woman aged 34, all from Blackpool, have been arrested on suspicion of wounding.
“Inquiries are continuing.”