Gardaí arrested three men and seized a quantity of cannabis herb in an operation yesterday evening.
Gardaí searched a house at Borlum Wood on the Green Road in Carlow town at approximately 8pm.
They seized seven kilograms of cannabis herb in an upstairs room.
In another room, they discovered a total of 100 cannabis plants at various stages of growth.
Authorities have estimated the drugs to have a street value of approximately €220,000.
Two men in their fifties and a man in his thirties, all Lithuanian nationals, were arrested at the scene.
They were taken to Carlow Garda Station where they are detained under Section 2 of the Criminal Justice (Drug Trafficking) Act, 1996.
The scene has been preserved overnight pending a full technical examination and the operation is ongoing.