A man walked into Mosta health centre with a gunshot wound on Wednesday morning, the police said in a statement.
The 43-year-old Dingli man entered the health centre shortly after 6am after having been allegedly wounded during an argument in his home town.
He is believed to have been shot during an argument with another man in the San Ġakbu area of the the village.
A 53-year-old Dingli man is being held by police for further questioning.
Magistrate Neville Camilleri is leading an inquiry into the incident.