The 49-year-old was detained after a man in his 30s was shot in north Belfast last night.
He is currently being quizzed at the serious crime suite at Musgrave PSNI station in Belfast.
The victim was rushed to hospital after being shot at a house in Ardoyne in north Belfast.
Police said the incident happened at Cranbrook Gardens on Friday evening.
The man was shot in the upper body from close range.
The Belfast Trust said he is in a stable condition in the Royal Victoria Hospital in west Belfast.