The unarmed gardaí apprehended the gunman after a 400-yard chase through the Thomondgate area.
A man who is being held under Section 30 of the Offences Against the State Act is due before Limerick District Court today on a firearms charge.
Garda Niamh Brosnan, from Co Cork, Garda Caimin Treacy from Co Clare and Garda Chris McGrath from Cork city were on foot patrol in Thomondgate on Tuesday night when they heard a shot. They saw the gunman running from the scene and gave chase on foot.
Garda McGrath, who is stationed in Mayorstone, said: “We chased him for about 400 yards.
“He was holding the gun in his hand. As we closed in on him he threw the weapon into a garden and we caught him.”
During a follow-up search, a sawn-off shot gun was recovered.
The three uniformed gardaí are part of an ongoing special operation in the north side of Limerick to counter late night crime.
The shooting happened at around 11.20pm.
Superintendent Gerry Mahon of Henry Street, who has deployed extra foot patrols, said: “The additional street patrols have worked very well. I would like to praise the courage of the three members who dealt with a potentially very dangerous situation in a very professional manner.
“We are proud that we have such dedicated members of the force out there doing their duty and serving the public.”
Garda McGrath who has been stationed in the city for the past four years said the night foot patrols have been very successful.
He said: “I think our presence in certain areas late at night is making a huge difference. You have to be out there to keep a lid on tings. Limerick is great and I love the city.”
Three uniformed gardaí narrowly escaped injury some months ago when their patrol car was hit by a shotgun blast at as it travelled through Moyross.
Six people were arrested in a follow-up operation and a man is due before Limerick Circuit Court.