A 46-year-old man, Christopher Ellul, was injured when roof slabs (xorok) caved at a building in St Ursola Street, Valletta and he fell through a hole.
He fell around one-and-a-half-storeys in what was probably a sitting room.
An ambulance rushed Mr Ellul to hospital. No other people were injured.
Sources said there does not seem to be any ongoing work on site. The victim lives there with his sister, who was on the second floor at the time of the accident.
The Civil Protection Department is on site.