A handgun was discovered in the garden of a Toxteth home on Sunday morning.
Police search teams also found bullets after officers raided a property on Princes Road.
A man has been arrested and is set to be questioned by detectives.
Officers from Merseyside Police's specialist Matrix outfit executed a warrant at the site at 10.10am.
The force said the gun was then found in the garden along with ammunition. Both will undergo forensics tests.
A 53-year-old man from Liverpool was arrested on suspicion of possession of a firearm.
Detective Inspector Tony Roberts said: “Our streets are made safer with every weapon we take out of circulation and every arrest we make in relation to firearms. I am delighted that we were able to recover this weapon and prevent it from causing fear and harm in our communities.
“We are committed to taking weapons off our streets and, rest assured, if you tell us about any suspected possession or offences we will take action and put those responsible before the courts.”
*Anyone with details about the suspected storage, possession and use of guns and ammunition can contact Merseyside Police via Twitter (@MerPolCC), Facebook (Merseyside Police Contact Centre) or by calling 101.
You can also contact Crimestoppers, anonymously, on 0800 555 111 or online here.
