A 32-year-old man from Bangladesh was seriously injured after he fell a considerable height at a construction site in Depiro Street in Sliema at 8.15am.
The man resides in Gżira, the police said.
He has been hospitalised for treatment - while investigations remain under way.
Just two hours later, a 29-year-old Somali man was also seriously injured after he was hit by falling bricks at a plant in Pembroke.
The police gave no other details of the accident.