A gun, bullets and €30,000 of cocaine were found in raids on two houses last night.
A man and a teenage girl were arrested after two homes were searched in the Inchicore area of west Dublin.
A garda spokesman said €20,000 of cocaine, an automatic pistol and rounds of ammunition were found in one house and €10,000 of cocaine in the second.
The firearm was taken for ballistic tests.
The arrested man, in his late teens, is being held under section two of the Criminal Justice (Drug Trafficking) Act 1996 at Kevin Street Garda Station.
The teenage girl, arrested in the second house, was later released without charge and a file will be prepared for the Director of Public Prosecutions.