A man working on the roof of a residence in St Paul's Bay was injured when fell around one storey at around 2.45 p.m. and is in a critical condition.
The police said, the 52-year-old man, from Mosta, was working in Triq ir-Ramel.
The man was assisted by the Civil Protection Department and the police before he was taken to hospital by ambulance.
An inquiry is being held.