A flat in the city centre was searched at around 9pm last night
Gardaí say drugs worth an estimated €300,000 have been seized in Dublin.
At around 9pm last night, a search was carried out by gardaí attached to the Street Crime Unit at a flat in the Whitefriar Gardens Flat Complex, Dublin 8.
During the search, heroin and mixing agent were discovered with a potential street value of €250,000.
Cocaine and crack cocaine with a street value of €50,000 was also found.
A 56-year-old man was arrested at the scene.
He is being detained at Kevin Street Garda Station, where he can be held for up to seven days.
Gardaí say their investigations are ongoing.
It was Wednesday's second major drugs bust in Dublin.
In a separate operation, drugs worth more than €2.8 million were seized following searches of two cars and a premises in Drumcondra.
A 25-year-old man is due to appear before Dublin District Court this morning, charged in connection with that investigation.