It is believed that gardaí, acting on intelligence gathering, raided the isolated house near the village of Tarelton and discovered a sophisticated growing operation inside.
The house had been converted and fitted out with lighting, heating and watering equipment to bring the plants to maturity as speedily as possible.
Members of the West Cork Divisional Drugs Squad, assisted by gardaí from Macroom, swooped on the house at Ron Na Killa, Tarelton on Wednesday.
Many of the plants were nearing maturity and were ready for harvesting.
Detectives arrested a 31-year-old Polish man at the scene.
He was being detained under Section 2 of the Criminal Justice (Drug Trafficking) Act 1996.
Under that legislation he can be held for up to seven days before either being charged or released.